damage vs impair

damage is a noun but impair is not a noun.

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

As verbs, impair is a hyponym of damage; that is, impair is a word with a more specific, narrower meaning than damage:

damage (noun)	impair (noun)
the act of damaging something or someone
any harm or injury resulting from a violation of a legal right
the occurrence of a change for the worse
loss of military equipment
the amount of money needed to purchase something

damage (verb)	impair (verb)
inflict damage upon	make worse or less effective
suffer or be susceptible to damage	make imperfect