avower vs declarer

avower and declarer both are nouns.

Word	Noun	Adjective	Verb	Adverb
avower	Yes	No	No	No
declarer	Yes	No	No	No

As nouns, avower and declarer are synonyms defined as:

Other synonyms of avower include affirmer, asserter, asseverator.

avower (noun)	declarer (noun)
someone who admits or acknowledges openly and boldly	the bridge player in contract bridge who wins the bidding and can declare which suit is to be trumps
someone who claims to speak the truth	someone who claims to speak the truth