Vocabulary B2 6 min read Updated 15 June 2026

Quick Answer

Conscience is a noun meaning your inner sense of right and wrong — the part of your mind that tells you whether something is moral (a guilty conscience, a clear conscience). Conscious is an adjective meaning awake and aware, or deliberately aware of something (a conscious decision, conscious of the risk). The related word conscientious is an adjective meaning careful and diligent.

Conscience and conscious are easy to confuse because they share a root and look almost identical, but they are completely different parts of speech with different meanings. Conscience is a noun about morality; conscious is an adjective about awareness. Once you fix the word class in your mind, choosing between them becomes straightforward. This is a classic B2-level trap, so it is worth learning carefully.

At a Glance: Conscience vs Conscious

WordPart of SpeechMeaningCommon Use
conscience Noun your inner sense of right and wrong; the moral faculty a guilty conscience, a clear conscience, in all conscience
conscious Adjective awake and aware; deliberately aware of something a conscious decision, conscious of the risk, fully conscious

Using “Conscience”

Conscience (pronounced /ˈkɒnʃəns/) is a noun. It names the inner voice or moral sense that tells you whether your actions are right or wrong. You can have a good conscience, a bad conscience, or be troubled by your conscience.

Definition

The part of your mind that judges whether what you do is morally right or wrong, often producing feelings of guilt when you do something wrong or peace when you act well. As a noun, it can be the subject or object of a sentence and takes articles such as a, the, my, or your.

When to use it

  • Talking about your sense of right and wrong: my conscience told me to apologise
  • In fixed phrases: a guilty conscience, a clear conscience, a troubled conscience
  • As the thing that troubles or guides you: his conscience kept him awake
  • In moral or ethical contexts: a matter of conscience, a conscientious objector
  • In the phrase in all conscience (= honestly, fairly)

After lying to her friend, she had a guilty conscience all week.

He returned the extra change because his conscience would not let him keep it.

I have a clear conscience — I did everything I could to help.

Voting against the bill was a matter of conscience for many MPs.

In all conscience, I cannot recommend this product to my customers.

Key Pattern

article + adjective + conscience: a guilty conscience, a clear conscience
possessive + conscience: my conscience, his conscience, your conscience
conscience as subject: her conscience troubled her all night

Using “Conscious”

Conscious (pronounced /ˈkɒnʃəs/) is an adjective. It describes someone who is awake and aware of their surroundings, or someone who is deliberately aware of a particular fact. Its opposite is unconscious.

Definition

1. Awake and able to perceive what is happening: the patient was conscious after the operation. 2. Deliberate, intentional, or aware of something: a conscious effort, conscious of the danger. As an adjective, it modifies a noun (a conscious choice) or follows a linking verb (she was conscious).

When to use it

  • Describing someone awake and aware: he stayed conscious throughout the journey
  • Meaning deliberate or intentional: a conscious decision, a conscious effort
  • With of to mean aware of something: conscious of the risk, conscious of her mistakes
  • In compounds: self-conscious, health-conscious, environmentally conscious
  • As the opposite of unconscious in medical or everyday contexts

The driver was still conscious when the ambulance arrived.

We made a conscious decision to spend less money this year.

She was very conscious of the noise her shoes made on the wooden floor.

He made a conscious effort to speak more slowly during the presentation.

As a health-conscious family, they rarely eat fast food.

Key Patterns

conscious + noun: a conscious decision, a conscious effort
be + conscious: the patient is conscious / she was conscious
conscious + of: conscious of the risk, conscious of his weaknesses

Noun vs Adjective: The Most Important Difference

The single biggest difference between conscience and conscious is their word class. Conscience is a noun — a thing you have, like a guilty conscience. Conscious is an adjective — a quality that describes a person or action, like a conscious choice. If the word is the name of a thing you possess, it is conscience; if it describes a state of being awake or aware, it is conscious.

Noun (conscience):

Her conscience would not let her keep the money.

Adjective (conscious):

She made a conscious choice to give the money back.

A useful test: try replacing the word with another noun like sense of morality. If that works, the answer is conscience. If instead you could replace it with aware or deliberate, the answer is conscious.

Common Mistakes

I have a guilty conscious about forgetting her birthday.

I have a guilty conscience about forgetting her birthday. (the noun, your moral sense)

He made a conscience decision to change careers.

He made a conscious decision to change careers. (the adjective, meaning deliberate)

After the accident, she was not conscience for several minutes.

After the accident, she was not conscious for several minutes. (the adjective, meaning awake)

Let your conscious be your guide.

Let your conscience be your guide. (the noun, your moral sense)

Special Expressions and the Word “Conscientious”

Several common expressions are fixed with conscience (the noun):

  • a clear conscience — no feelings of guilt: I can sleep with a clear conscience
  • a guilty conscience — feelings of guilt: his guilty conscience showed on his face
  • in all conscience — honestly and fairly: I cannot, in all conscience, accept the offer
  • on your conscience — making you feel guilty: the mistake was on her conscience for years

And several are fixed with conscious (the adjective):

  • a conscious decision / effort / choice — a deliberate one
  • conscious of — aware of: conscious of the time
  • self-conscious — nervously aware of yourself: she felt self-conscious on stage
  • health-conscious / environmentally conscious — caring about that thing

Two related words often join the confusion. Conscientious (/ˌkɒnʃiˈenʃəs/) is an adjective meaning careful, diligent, and hard-working: a conscientious student who never misses a deadline. Consciousness is a noun meaning the state of being aware or awake: she lost consciousness for a moment. Notice that conscientious and conscience share the moral, careful idea, while consciousness and conscious share the awareness idea.

Memory Tip

Remember the spelling by the ending. ConscienCE ends like scienCE — and it is a noun, just as science is a noun. ConsciouS ends in -ous like many adjectives (famous, nervous, dangerous) — and it is an adjective. So: scienCE = conscienCE = noun; -ouS = consciouS = adjective. If you can spot whether you need a thing (noun) or a description (adjective), the spelling follows automatically.

Frequently Asked Questions

What is the difference between conscience and conscious?
Conscience is a noun meaning your inner sense of right and wrong — the moral part of your mind that tells you whether something is good or bad (a guilty conscience, a clear conscience). Conscious is an adjective meaning awake and aware, or deliberately aware of something (a conscious decision, conscious of the risk). The simplest way to keep them apart is by word class: conscience names a thing you have, while conscious describes a state or a deliberate action.
Is conscience a noun or an adjective?
Conscience is a noun. It names the moral faculty inside you — the sense that judges whether your actions are right or wrong. Because it is a noun, it takes articles and possessives: a conscience, the conscience, my conscience, his conscience. You cannot use it to describe a noun the way an adjective would, so phrases like "a conscience decision" are wrong. The correct adjective for "aware" or "deliberate" is conscious.
What does conscious mean?
Conscious is an adjective with two main meanings. First, it means awake and able to perceive what is happening around you: the patient was conscious after surgery. Its opposite in this sense is unconscious. Second, it means deliberate or aware of something: a conscious decision, conscious of the risk. When followed by of, it means aware of a particular fact: she was conscious of the time. It often appears in compounds such as self-conscious and health-conscious.
What does conscientious mean?
Conscientious is an adjective meaning careful, diligent, and thorough, especially about doing your work or duties properly. A conscientious student checks their work, meets deadlines, and takes their responsibilities seriously. It shares a root with conscience because a conscientious person listens to their sense of duty. Do not confuse it with conscious: conscientious is about being careful and hard-working, while conscious is about being awake or deliberately aware. A conscientious objector, for example, refuses military service on moral grounds.
What is the difference between a guilty conscience and a clear conscience?
Both phrases use the noun conscience. A guilty conscience means you feel troubled or ashamed because you believe you have done something wrong: he had a guilty conscience after telling the lie. A clear conscience means the opposite — you feel no guilt because you believe you have acted rightly: she returned the money and now has a clear conscience. These are fixed expressions, so the noun conscience is always correct here, never conscious.
Why is it "a conscious decision" and not "a conscience decision"?
A conscious decision means a deliberate, intentional decision — one you made while fully aware. Here you need an adjective to describe the noun decision, and conscious is the adjective. Conscience is a noun, so it cannot modify another noun in this way. So "a conscience decision" is incorrect. Remember that adjectives like conscious, careful, and deliberate go in front of nouns to describe them, while conscience is itself the name of a thing.
What is an easy way to remember the spelling?
Look at the endings. Conscience ends in -ence, like the word science — and like science it is a noun. Conscious ends in -ous, the same ending found in many adjectives such as famous, nervous, and dangerous — and it is an adjective. So conscienCE = science = noun, and consciouS with its -ous ending = adjective. If you decide first whether you need a thing (noun) or a describing word (adjective), the correct spelling follows.
What is the difference between consciousness and conscience?
Both are nouns, but they mean different things. Consciousness is the state of being awake and aware: she lost consciousness after the fall and regained consciousness in hospital. It comes from the adjective conscious. Conscience is your inner sense of right and wrong: his conscience would not let him cheat. It is connected to morality, not to being awake. So consciousness is about awareness and wakefulness, while conscience is about ethics and guilt.
How do you pronounce conscience and conscious?
Conscience is pronounced /ˈkɒnʃəns/ — roughly "KON-shuhnss," with two syllables and a soft "sh" sound in the middle. Conscious is pronounced /ˈkɒnʃəs/ — roughly "KON-shuhss," also two syllables. The two words sound very similar, which is part of why they are confused, but conscience ends in a softer "-uhnss" sound while conscious ends in a sharper "-uhss." Saying them aloud and listening for that final sound can help you tell them apart.
Is there a memory trick to tell conscience and conscious apart?
Yes. Link conscience with the idea of right and wrong: "my conscienCE knows what's nicE" — both end in -ce, and it is the noun about morality. Link conscious with "aware": think "I am consciouS and curiouS" — both -ous adjectives describing how you are. Another trick: conscience contains the whole word science, reminding you it is a noun. Once you connect conscience to morality (noun) and conscious to awareness (adjective), the rest follows naturally.

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