offshore vs seaward

offshore is not a noun while seaward is a noun.

Word	Noun	Adjective	Verb	Adverb
offshore	No	Yes	No	Yes
seaward	Yes	Yes	No	Yes

As adjectives, offshore and seaward are synonyms defined as:

offshore (noun)	seaward (noun)
	the direction toward the sea

offshore (adjective)	seaward (adjective)
(of winds) coming from the land	(of winds) coming from the land
at some distance from the shore	directed or situated away from inland regions and toward the sea or coast

offshore (adverb)	seaward (adverb)
away from shore; away from land	in the direction of the sea