against the wind vs upwind

against the wind is not an adjective while upwind is an adjective.

Word	Noun	Adjective	Verb	Adverb
against the wind	No	No	No	Yes
upwind	No	Yes	No	Yes

As adverbs, against the wind and upwind are synonyms defined as:

against the wind and upwind: in the direction opposite to the direction the wind is blowing

Other synonyms of against the wind include into the wind.

against the wind (adjective)	upwind (adjective)
	towards the side exposed to wind

against the wind (adverb)	upwind (adverb)
in the direction opposite to the direction the wind is blowing	in the direction opposite to the direction the wind is blowing
	away from the wind