seaward vs offshore

seaward is a noun but offshore is not a noun.

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

As adjectives, seaward and offshore are synonyms defined as:

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

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

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