heighten vs heat up

heighten and heat up both are verbs.

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

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

Other hyponyms of heighten include hot up, screw up, fan, enhance, heighten, raise, amplify, sharpen, heighten, sharpen.

heighten (verb)	heat up (verb)
increase the level of	make hot or hotter
become more extreme	gain heat or get hot
make more extreme; raise in quantity, degree, or intensity	make more intense
make more intense, stronger, or more marked
make (one's senses) more acute
increase the height of