Synonyms of certainly
42 similar words · 7 opposite words
Another word for certainly is sure. Other synonyms of certainly are surely, positively, doubtless, indubitably and assuredly. The opposite of certainly is uncertainly.
Synonyms and similar words for certainly
adverbIn a way which is certain; with certainty.
- absolutely
- beyond doubt
- indubitablyIn a manner that leaves no possibility of doubt.
- sure thing
- undoubtedlyWithout doubt; definitely.
- without a doubtCertainly; doubtlessly; unquestionably; indisputably; doubtless; surely; no doubt; without any doubt.
- wis obsoleteCertainly, surely.
adverbWithout doubt, surely.
- definitely
- doubtlessly
- in fact
- indeed
- indisputablyIn a manner that is incapable of being disputed or argued against.
- no doubtWithout a doubt; surely.
- really
- sureWithout doubt, certainly.
- surelyCertainly, undoubtedly.
- truly
- unquestionably
- rightly informalIn a right manner; correctly, justifiably.
adverbMore synonyms
- damn rightExpresses enthusiastic support or opposition, agreement or disagreement, certainty or emphasis.
- damn straightWithout doubt, certainly, for sure.
- fo shizzleFor sure; of course; right on.
- for sureDefinitely, positively, without a doubt.
- oh yeah
- wye aye dialectalA positive yes, of course.
- assuredlyFor sure; certainly.
- categorically
- decisivelyIn a decisive manner.
- doubtlessWithout doubt; certainly; definitely; very probably, in all likelihood; doubtlessly.
- ex facie
- for a fact
- for certainDefinitely, positively, without doubt.
- positivelyWith certainty.
- questionlesslyIn a questionless manner; assuredly.
- self-evidentlyIn a self-evident manner.
- unarguablyInarguably (Certainly; without the possibility of argument or debate).
- undeniably
- unconditionallyWithout condition, absolutely.
- undoubtablyWithout doubt.
- univocallyIn a univocal manner.
- without doubt
- without question
Opposite of certainly
adverbMore antonyms
- arguablyAs can be supported or proven by sound logical deduction, evidence, and precedent, but without absolute certainty.
- conditionallyUnder specified conditions.
- debatablyIn a way subject to challenge or worthy of debate.
- deniablyIn a deniable manner.
- doubtfullyIn a doubtful manner, in context of doubt or ambiguity, questionably.
- questionablyIn a questionable manner.
- uncertainlyIn an uncertain manner.
Meaning of certainly
- adverb In a way which is certain; with certainty.
- adverb Without doubt, surely.
- adverb An emphatic affirmative answer; of course.
certainly in other languages
Questions about synonyms of certainly
- What is another word for certainly?
- Certainly has 42 synonyms on Word.ws, such as sure, surely, positively, doubtless, indubitably, assuredly, undoubtably and unarguably.
- What is the opposite of certainly?
- The opposite of certainly is uncertainly. Other antonyms of certainly are arguably, conditionally and questionably.
- What does certainly mean?
- Certainly means in a way which is certain; with certainty.
Source and license
Adapted from Wiktionary: certainly (page history and authors) and the entries of the words listed. Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws grouped the synonyms and antonyms by meaning and added links. Wiktionary data of 2026-09-02.
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Cite this page: “Synonyms of certainly.” Word.ws, https://word.ws/synonyms/certainly. Based on Wiktionary, CC BY-SA 4.0.