Quick Definition
Diligent (adjective) describes a person who works hard and carefully, paying close attention to detail and continuing patiently until a task is done properly.
Example: "He is a diligent worker who never leaves a job half-finished."
What Does Diligent Mean?
The word diligent comes from the Latin diligere, meaning "to value highly" or "to take care of." It entered English through Old French in the 14th century. At its heart, being diligent means caring enough about your work to do it carefully, steadily, and right to the end.
In modern English, diligent is a high-value character adjective used to praise students, employees, and professionals. It combines two ideas: effort (working hard) and care (working thoroughly). You will often see it in school reports, job references, and appraisals — for example "a diligent and reliable student" or "diligent in meeting deadlines."
Key point: diligent is not just about being busy. A person can be busy without being diligent. Diligence implies steady, careful, conscientious effort directed at doing a task well — which is why it is such a strong word in formal and professional contexts.
Example Sentences
| Sentence | Level / Note |
|---|---|
| She is a diligent student who reviews her notes every evening. | B2 — education / character description |
| Thanks to diligent preparation, the team passed the inspection with no faults. | B2 — workplace / neutral register |
| The detective was diligent in checking every alibi before drawing a conclusion. | B2 — narrative / journalism |
| Investors carried out diligent research before committing their funds. | C1 — business / formal register |
| Only through diligent and patient effort did the scholars reconstruct the lost manuscript. | C1 — academic / literary register |
Word Family
Adjective
diligent
"A diligent worker."
Noun
diligence
"Her diligence paid off."
Adverb
diligently
"He worked diligently."
No verb form
—
Say: "exercise diligence."
Synonyms & Antonyms
Synonyms
- hard-working — putting in a lot of effort
- industrious — constantly busy and productive
- conscientious — careful and thorough about doing things right
- assiduous — showing great care and persistence
- meticulous — paying very close attention to detail
Antonyms
- negligent — failing to take proper care
- lazy — unwilling to work or make an effort
- careless — not paying enough attention
- idle — avoiding work; doing nothing
- slack — not working hard enough
Common Collocations
- a diligent student / worker — "She is a diligent student with excellent habits."
- diligent research / preparation — "Diligent research is the key to a strong report."
- remarkably diligent — "The new intern is remarkably diligent."
- diligent in (doing) something — "He is diligent in meeting every deadline."
- due diligence — "The buyer carried out due diligence before the sale." (noun form)
- work / study diligently — "They studied diligently for the exam." (adverb form)
Related Words
Practise This Word
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Frequently Asked Questions about “diligent”
What does diligent mean in English?
Diligent means showing careful, steady, and persistent effort in your work or duties. A diligent person is hard-working and thorough, paying close attention to detail and continuing patiently until a task is finished properly. For example: 'She is a diligent student who reviews her notes every evening.' It carries a strongly positive tone and is common in school reports, references, and the workplace.
How do you pronounce diligent?
Diligent is pronounced /ˈdɪlɪdʒənt/. It has three syllables: DIL-i-juhnt. The main stress falls on the first syllable: DIL. The middle 'g' makes a soft /dʒ/ (j) sound, as in 'gentle', not a hard /g/. Say it slowly: DIL... i... juhnt.
What is the CEFR level of diligent?
Diligent is a B2 (Upper-Intermediate) level word. It appears often in academic references, job applications, school reports, and professional feedback. B2 learners are expected to use precise character adjectives like diligent rather than only basic words such as 'hard-working'.
What are synonyms for diligent?
Synonyms for diligent include: hard-working (putting in a lot of effort), industrious (constantly busy and productive), conscientious (careful and thorough about doing things right), assiduous (showing great care and persistence), and meticulous (paying very close attention to detail). Diligent often emphasises both effort and steady attention to detail at the same time.
What are antonyms of diligent?
Antonyms of diligent include: negligent (failing to take proper care), lazy (unwilling to work or make an effort), careless (not paying enough attention), idle (avoiding work), and slack (not working hard enough). You might contrast: 'A diligent inspector checks every detail, while a negligent one signs off without looking.'
What is the noun form of diligent?
The noun form is diligence (/ˈdɪlɪdʒəns/): 'Her diligence impressed the whole team.' It also appears in the fixed legal and business phrase 'due diligence', meaning careful checking before a decision. The adverb is diligently: 'He worked diligently through the night.' There is no common verb form.
What are common collocations with diligent?
Common collocations with diligent include: a diligent student, a diligent worker, diligent research, diligent effort, diligent preparation, and remarkably diligent. With the noun form you will see 'due diligence', 'exercise diligence', and 'with great diligence'. The adverb collocates as 'work diligently' and 'study diligently'.
Is diligent positive or negative?
Diligent is a strongly positive adjective. Describing someone as diligent is a compliment: it praises their work ethic, reliability, and attention to detail. This is why it appears so often in references, appraisals, and recommendation letters, where it signals that a person can be trusted to complete work carefully and on time.
What is the difference between diligent and hard-working?
Both describe effort, but diligent adds the idea of careful, methodical attention to detail and persistence over time. A hard-working person simply puts in a lot of effort; a diligent person works hard and works carefully, checking that the job is done properly. Diligent is also more formal, which is why it is preferred in academic and professional writing.
How can I practise the word diligent on LexFizz?
Use LexFizz's Flash Cards to practise diligent alongside related B2 adjectives like conscientious and industrious. The Vocabulary Quiz presents diligent in sentence context so you learn how it is used in references and reports, and the Wordsearch helps you fix the spelling — note the soft 'g'. Try writing two sentences: one about a student and one about an employee.