undoer vs wrecker

undoer and wrecker both are nouns.

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

As nouns, wrecker is a hyponym of undoer; that is, wrecker is a word with a more specific, narrower meaning than undoer:

Other hyponyms of undoer include annihilator, iconoclast, image breaker, diversionist, saboteur, vandal.

undoer (noun)	wrecker (noun)
a person who destroys or ruins or lays waste to	a truck equipped to hoist and pull wrecked cars (or to remove cars from no-parking zones)
a person who unfastens or unwraps or opens	someone who commits sabotage or deliberately causes wrecks
a seducer who ruins a woman	someone who demolishes or dismantles buildings as a job