I've seen affirm defined as "To say that something is true in a confident way." I've looked at various antonyms, and antonyms of synonyms of affirm and none seem appropriate. I'm wondering if there's a word that would be defined as, "To say that something is false in a confident way."

I also know that you can "affirm" a negative, but I'm looking to use affirm along with this other word similar to the way confirm/deny are used together.

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    I think I would have said deny is the word to use. Why is that not suitable?
    – Andrew Leach
    Jan 25 at 19:04
  • 4
    Have you rejected refute and rebut? Jan 25 at 19:38
  • 1
    The meaning of affirm as a verb is never negative. Do you affirm or deny you were present at the scene of the crime?
    – Lambie
    Jan 26 at 16:16

5 Answers 5


There is the word disaffirm.

TRANSITIVE VERB [with object]
Repudiate; declare void.
‘to disaffirm a contract is to say it never existed’
‘It was specifically disaffirmed by Justice Lindgren at trial.’
‘‘To a certain degree, that is correct,’ the Commander affirmed yet disaffirmed simultaneously.’
source: Lexico

  • 1
    But you don't affirm a contract, so disaffirm is not the opposite of affirm.
    – Lambie
    Jan 26 at 18:30
  • @Lambie, there is, in fact, such a thing as affirming a contract, although it is indeed not quite the opposite of what is defined here: if the circumstances arise that give one the right to terminate a contract, one can choose to affirm it instead.
    – jsw29
    Jan 27 at 16:51
  • This matches what I was looking for. Makes me wonder why "disaffirm" wasn't in the synonym/antonym lists. Jan 31 at 15:00

I see that Jack has suggested this, but here it's fleshed out:

refute [verb] [transitive] [formal]

1 to say that a statement is not true or accurate without giving proof

  • The police said he was drunk, a claim refuted by his attorney. ... dispute ...

2 to prove that a statement is false

  • The evidence refutes all claims that the student loan scheme is not working. [... rebut; Longmans]


The first sense here includes 'to say that a statement is wrong', and the pull of the second sense adds gravitas, so a firm denial.

However, the second sense is the default sense (listed as such by Longmans), and the two senses don't harmonise (ie they conflict).

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    I'd always seen rebut as "to provide argument against..." while refute is "to provide proof against...". Never seen them as synonyms
    – Jim Mack
    Jan 25 at 21:00
  • It should be noted that, as Lexico's usage note puts it 'traditionalists object to this newer use [1 in the quoted entry from Macmillan] as an unacceptable degradation of the language, but it is widely encountered'.
    – jsw29
    Jan 26 at 16:40
  • Yes. For 'rebut', CED has 'to say firmly and directly, or prove, that something is not true' in its Business Dictionary but 'to argue that a statement or claim is not true' (I'd say an intermediate sense) in two other of its publications. And for 'refute', 'to say or prove that a person, statement, opinion, etc. is wrong or false' AND 'to prove a statement, opinion, or belief to be wrong or false' in two of its dictionaries. Traditionalists can refute[L1] this usage of 'refute', but they can't refute[L2] it: common usage drives acceptability, and we're obviously in the messy broadening phase. Jan 26 at 17:20
  • Refute is valid, and the OED lists refute as a synonym of deny in the second sense (the Historical Thesaurus category is literally "refute, disprove [verb (transitive)]"). Good choice if someone wants to avoid deny. Jan 26 at 19:04

As Mr. Leach has already pointed out in a comment, the most obvious word to use for this purpose is deny. Oxford English Dictionary, "deny, v.," definition 2:

Logic. The opposite of affirm; to assert the contradictory of (a proposition).

(This may be so obvious that it is arguable that the question should have been closed. Given that it hasn't been, and that it has already received a couple of other answers, this obvious answer needs to be posted as such.)

  • I agree. Very obvious.
    – Lambie
    Jan 26 at 18:30
  • Yes; the only reason I posted the answer was because of the complication of the divided usage surrounding the two senses of 'refute'. Jan 26 at 19:22
  • I don't like deny, because it feels like that the assertion is true, but the speaker is contesting the truth of it. Jan 31 at 14:59

I would say negate is a possibility (Merriam-Webster), although it is (in my experience) more commonly used in the second sense below (and "deny" is much more common — it's used in the definition of "negate" below ...)

transitive verb 1 : to deny the existence or truth of
negated and denied her own honest reactions— Sara H. Hay
2 : to cause to be ineffective or invalid
Alcohol can negate the effects of some medicines.


Repudiate, renounce or disavow.

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