proof has 6 distinct synonyms spread across 4 of its 12 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
any factual evidence that helps to establish the truth of something
“if you have any proof for what you say, now is the time to produce it”
a formal series of statements showing that if one thing is true something else necessarily follows from it
a measure of alcoholic strength expressed as an integer twice the percentage of alcohol present (by volume)
(printing) an impression made to check for errors
a trial photographic print from a negative
the act of validating; finding or testing the truth of something
make or take a proof of, such as a photographic negative, an etching, or typeset
knead to reach proper lightness
“proof dough”
activate by mixing with water and sometimes sugar or milk
“proof yeast”
make resistant (to harm)
“proof the materials against shrinking in the dryer”
1 of the 12 recorded senses carries no synonym, antonym or related term, so it is not shown above. Every sense, with its definition and examples, is on the full entry for proof.
Synonyms, antonyms and the broader and narrower relations for proof come from Princeton University’s WordNet. Full sources and licences.