probably

probably — adverb

1. You use probably to say that you think something is true or will happen, but you

1.adverbA2
Definition

You use probably to say that you think something is true or will happen, but you are not completely certain.

Example

Joshua is probably still at work — I can see his car in the car park.

probably after BE: is probably

If you do not eat breakfast, you will probably feel hungry before lunch.

will probably + verb in conditional sentence

Synonyms
  • likely

    adjective only; requires 'to' or 'that' (It is likely to rain / It is likely that…), while 'probably' is an adverb that modifies the verb directly.

  • presumably

    more formal; suggests the speaker is reasoning from available evidence rather than just guessing.

  • doubtless

    stronger certainty and more formal; usually used in written English.

Antonyms
  • possibly

    suggests a much lower chance (maybe 30%) compared to 'probably' (over 50%).

  • maybe

    more informal and less certain than 'probably'; often used in casual conversation.

Grammar Patterns

probably + verb phrase

probably after be

probably before main verb

Usage Note

Probably is a sentence adverb and usually sits in mid-position: after the verb BE (is probably), after the first auxiliary verb (will probably), or directly before the main verb (probably forgot). In informal speech, it may begin a sentence: Probably she's already left.

Common Mistakes

It is probably that she is right.
It is probable that she is right.
'Probably' is an adverb and cannot follow 'is' before a 'that' clause. Use the adjective 'probable' instead.
I probably will go to the party.
I will probably go to the party.
In standard English, 'probably' usually comes after 'will', not before it.

Word family

Synonym discussion

Sense: adverb/1

All four words express the speaker's belief that something is true or will happen, but they differ in certainty level and formality. Probably is the most neutral and common — it simply says the chance is above 50%. Likely is an adjective, not an adverb (the adverbial form is 'likely' in informal US English, but standard grammar prefers 'probably' in verb-modifying positions). Presumably adds a reasoning step: the speaker is inferring based on logic or evidence ('Presumably the office is closed if it is a holiday'). Doubtless is the strongest and most formal — it leaves almost no room for doubt, and is more common in written than spoken English. For everyday conversation, probably covers most situations.

probably ↗likely ↗presumably ↗doubtless ↗

Common collocations

Adverbs

Phrases

  • will probably
  • probably won't
  • probably should
  • probably would
  • probably going to

Etymology

LatinFrenchEnglish

Probably comes from the adjective probable (meaning 'likely to happen or be true') plus the adverb suffix -ly. Probable entered English from French in the 1300s, and traces back to the Latin word probabilis, which meant 'that can be proved' or 'worthy of approval'. Over time, the meaning shifted from 'provable' to 'likely'.