swear vs avow

swear and avow both are verbs.

Word	Noun	Adjective	Verb	Adverb
swear	No	No	Yes	No
avow	No	No	Yes	No

As verbs, swear and avow are synonyms defined as:

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

swear (verb)	avow (verb)
have faith or confidence in	to declare or affirm solemnly and formally as true
make a deposition; declare under oath	admit openly and bluntly; make no bones about
utter obscenities or profanities
promise solemnly; take an oath
to declare or affirm solemnly and formally as true