opener vs undoer

opener and undoer both are nouns.

Word	Noun	Adjective	Verb	Adverb
opener	Yes	No	No	No
undoer	Yes	No	No	No

As nouns, opener and undoer are synonyms defined as:

Other synonyms of opener include unfastener, untier.

opener (noun)	undoer (noun)
a hand tool used for opening sealed containers (bottles or cans)	a person who destroys or ruins or lays waste to
the first event in a series	a person who unfastens or unwraps or opens
a person who unfastens or unwraps or opens	a seducer who ruins a woman