crest vs mountain peak

crest and mountain peak both are nouns.

Word	Noun	Adjective	Verb	Adverb
crest	Yes	No	Yes	No
mountain peak	Yes	No	No	No

As nouns, mountain peak is a hyponym of crest; that is, mountain peak is a word with a more specific, narrower meaning than crest:

Other hyponyms of crest include brow, hilltop, pinnacle.

crest (noun)	mountain peak (noun)
a showy growth of e.g. feathers or skin on the head of a bird or other animal	the summit of a mountain
(heraldry) in medieval times, an emblem used to decorate a helmet
the center of a cambered road
the top line of a hill, mountain, or wave
the top or extreme point of something (usually a mountain or hill)

crest (verb)	mountain peak (verb)
reach a high point
lie at the top of