hilltop vs peak

hilltop and peak both are nouns.

Word	Noun	Adjective	Verb	Adverb
hilltop	Yes	No	No	No
peak	Yes	No	Yes	No

As nouns, peak is a hypernym of hilltop; that is, peak is a word with a broader meaning than hilltop:

Other hypernyms of hilltop include crest, crown, summit, tip, top.

hilltop (noun)	peak (noun)
the peak of a hill	a brim that projects to the front to shade the eyes
	the top or extreme point of something (usually a mountain or hill)
	the highest point (of something)
	the most extreme possible amount or value
	a V shape
	the highest level or degree attainable; the highest stage of development
	the period of greatest prosperity or productivity

hilltop (verb)	peak (verb)
	to reach the highest point; attain maximum intensity, activity