promote vs foster

promote is not an adjective while foster is an adjective.

Word	Noun	Adjective	Verb	Adverb
promote	No	No	Yes	No
foster	No	Yes	Yes	No

As verbs, foster is a hyponym of promote; that is, foster is a word with a more specific, narrower meaning than promote:

Other hyponyms of promote include connive at, wink at, cultivate, further, spur, help, carry, feed, conduce, contribute, lead.

promote (adjective)	foster (adjective)
	providing or receiving nurture or parental care though not related by blood or legal ties

promote (verb)	foster (verb)
make publicity for; try to sell (a product)	help develop, help grow
change a pawn for a better piece by advancing it to the eighth row, or change a checker piece for a more valuable piece by moving it to the row closest to your opponent	promote the growth of
be changed for a superior chess or checker piece	bring up under fosterage; of children
give a promotion to or assign to a higher position
contribute to the progress or growth of