Probably is an adverb meaning almost certainly or very likely. It signals a high degree of confidence — usually around 70–90% — while leaving open a small possibility of being wrong.
What Does Probably Mean?
Probably comes from the Latin probabiliter, meaning "in a credible or provable manner", from probabilis (credible, testable) and ultimately from probare (to test, to prove). The same Latin root gives English the words probe, proof, approve, and probability. The word entered Middle English via Medieval Latin in the late 15th century and has been one of the most common adverbs in the language ever since.
In everyday use, probably occupies a specific position on the scale of certainty. It sits above possibly and perhaps (which express weaker confidence) but below certainly and definitely (which leave no room for doubt). When you say "It will probably rain", you are predicting rain with strong confidence while acknowledging that forecasts can be wrong.
Understanding probably is essential at A2 level and above. It appears constantly in news reports, academic writing, conversation, and emails. Native speakers use it to soften predictions, give opinions diplomatically, and hedge claims without sounding unsure.
Etymology
From Latin probabiliter → adjective probabilis → verb probare (to test, to prove). The root probare also underlies probe, proof, approve, reprove, and probability. Probably entered written English around the late 15th century, with early uses meaning "in a way that can be demonstrated or proved". Over time the sense shifted from "provably" to "in all likelihood".
Example Sentences
| Sentence | Level & note |
|---|---|
| I am probably going to the shops later. | A2 — simple present plan; probably before main verb |
| She will probably finish her homework before dinner. | B1 — future prediction; probably after modal |
| The most difficult part of the exam is probably the writing section. | B1 — opinion / evaluation; probably after to be |
| The delays are probably caused by the ongoing roadworks near the city centre. | B2 — passive construction; hedged explanation |
| This shift in consumer behaviour is probably the most significant structural change the retail sector has witnessed in decades. | C1 — academic register; hedging a strong analytical claim |
Usage Notes
Position before the main verb: In most sentences, probably comes immediately before the main verb: "They will probably leave early." With the verb to be, it follows the verb: "He is probably right." This is the neutral, most frequent position.
Negative sentences: Place probably before the negative word for natural word order: "She probably won't come." Saying "She won't probably come" sounds unnatural in standard British English.
Sentence-initial use: Probably can open a sentence for emphasis: "Probably the best decision you can make is to practise every day." This is more emphatic and slightly more formal.
Degree of certainty: Probably implies roughly 70–90% confidence. If you are less certain, use possibly or perhaps. If you are certain, use definitely or certainly.
Collocations
| Collocation | Example |
|---|---|
| probably the best | It is probably the best film I have seen this year. |
| probably the most | Grammar is probably the most studied area of language. |
| probably won't | He probably won't arrive until after eight. |
| probably would | I would probably choose the second option. |
| quite probably | This is quite probably the hardest exercise in the set. |
| very probably | The match will very probably be postponed due to rain. |
| probably never | We will probably never know the full story. |
| probably already | She has probably already heard the news. |
| probably just | It is probably just a minor technical issue. |
| more probably | The cause is stress, or more probably a combination of factors. |
Common Mistakes
Watch Out For
She won't probably come to the party.
She probably won't come to the party. (probably before the negative)
Probably he is at home.
He is probably at home. (sentence-initial use is possible but less natural for simple statements)
I am probably sure about this.
I am fairly sure about this. (do not combine probably with certain/sure — they contradict each other)