assist vs subserve

assist is a noun but subserve is not a noun.

Word	Noun	Adjective	Verb	Adverb
assist	Yes	No	Yes	No
subserve	No	No	Yes	No

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

assist (noun)	subserve (noun)
(sports) the act of enabling another player to make a good play
the activity of contributing to the fulfillment of a need or furtherance of an effort or purpose

assist (verb)	subserve (verb)
act as an assistant in a subordinate or supportive function	be helpful or useful
work for, or be a servant to
give help or assistance; be of service