heat up vs crisp

heat up is not a noun while crisp is a noun.

Word	Noun	Adjective	Verb	Adverb
heat up	No	No	Yes	No
crisp	Yes	Yes	Yes	No

As verbs, crisp is a hyponym of heat up; that is, crisp is a word with a more specific, narrower meaning than heat up:

Other hyponyms of heat up include crispen, toast, scald, soak, calcine, preheat, overheat, scorch, sear, bake, broil, reheat.

heat up (noun)	crisp (noun)
	a thin crisp slice of potato fried in deep fat

heat up (adjective)	crisp (adjective)
	pleasantly cold and invigorating
	brief and to the point; effectively cut short
	(of hair) in small tight curls
	(of something seen or heard) clearly defined
	pleasingly firm and fresh
	tender and brittle

heat up (verb)	crisp (verb)
make hot or hotter	make brown and crisp by heating
gain heat or get hot	make wrinkles or creases on a smooth surface; make a pressed, folded or wrinkled line in; `crisp' is archaic
make more intense