westerly vs west wind

westerly and west wind both are nouns.

Word	Noun	Adjective	Verb	Adverb
westerly	Yes	Yes	No	Yes
west wind	Yes	No	No	No

As nouns, west wind is a hypernym of westerly; that is, west wind is a word with a broader meaning than westerly:

westerly: the winds from the west that occur in the temperate zones of the Earth
west wind: wind that blows from west to east

Other hypernyms of westerly include wester.

westerly (noun)	west wind (noun)
the winds from the west that occur in the temperate zones of the Earth	wind that blows from west to east

westerly (adjective)	west wind (adjective)
of wind; from the west
moving toward the west

westerly (adverb)	west wind (adverb)
in a westward direction
from the west