air conditioner vs air-conditioner

air conditioner and air-conditioner both are nouns.

Word	Noun	Adjective	Verb	Adverb
air conditioner	Yes	No	No	No
air-conditioner	Yes	No	No	No

As nouns, air conditioner and air-conditioner are synonyms defined as:

air conditioner and air-conditioner: an appliance designed to extract humidity from the air and thereby cool it

Other synonyms of air conditioner include A/C.

air conditioner (noun)	air-conditioner (noun)
a system that keeps air cool and dry	an appliance designed to extract humidity from the air and thereby cool it
an appliance designed to extract humidity from the air and thereby cool it