affirm vs corroborate

affirm and corroborate both are verbs.

Word	Noun	Adjective	Verb	Adverb
affirm	No	No	Yes	No
corroborate	No	No	Yes	No

As verbs, affirm and corroborate are synonyms defined as:

affirm and corroborate: establish or strengthen as with new evidence or facts

Other synonyms of affirm include confirm, substantiate, support, sustain.

affirm (verb)	corroborate (verb)
establish or strengthen as with new evidence or facts	establish or strengthen as with new evidence or facts
to declare or affirm solemnly and formally as true	give evidence for
say yes to	support with evidence or authority or make more certain or confirm