repeal vs annul

repeal is a noun but annul is not a noun.

Word	Noun	Adjective	Verb	Adverb
repeal	Yes	No	Yes	No
annul	No	No	Yes	No

As verbs, repeal and annul are synonyms defined as:

Other synonyms of repeal include countermand, lift, overturn, rescind, reverse, revoke, vacate.

repeal (noun)	annul (noun)
the act of abrogating; an official or legal cancellation

repeal (verb)	annul (verb)
cancel officially	cancel officially
	declare invalid