spoil vs impair

spoil is a noun but impair is not a noun.

Word	Noun	Adjective	Verb	Adverb
spoil	Yes	No	Yes	No
impair	No	No	Yes	No

As verbs, spoil and impair are synonyms defined as:

Other synonyms of spoil include deflower, mar, vitiate.

spoil (noun)	impair (noun)
the act of stripping and taking by force
the act of spoiling something by causing damage to it
(usually plural) valuables taken by violence (especially in war)

spoil (verb)	impair (verb)
become unfit for consumption or use	make worse or less effective
alter from the original	make imperfect
make imperfect
destroy and strip of its possession
have a strong desire or urge to do something
hinder or prevent (the efforts, plans, or desires) of
treat with excessive indulgence
make a mess of, destroy or ruin