downwind vs leeward

downwind is not a noun while leeward is a noun.

Word	Noun	Adjective	Verb	Adverb
downwind	No	Yes	No	Yes
leeward	Yes	Yes	No	Yes

downwind (noun)	leeward (noun)
	the side of something that is sheltered from the wind
	the direction in which the wind is blowing

downwind (adjective)	leeward (adjective)
towards the side away from the wind	on the side away from the wind

downwind (adverb)	leeward (adverb)
with the wind; in the direction the wind is blowing	away from the wind
toward the wind