swan vs aver

swan is a noun but aver is not a noun.

Word	Noun	Adjective	Verb	Adverb
swan	Yes	No	Yes	No
aver	No	No	Yes	No

As verbs, swan and aver are synonyms defined as:

Other synonyms of swan include affirm, assert, avow, swear, verify.

swan (noun)	aver (noun)
stately heavy-bodied aquatic bird with very long neck and usually white plumage as adult

swan (verb)	aver (verb)
to declare or affirm solemnly and formally as true	to declare or affirm solemnly and formally as true
move about aimlessly or without any destination, often in search of food or employment	report or maintain
sweep majestically