weigh vs heft

weigh is not a noun while heft is a noun.

Word	Noun	Adjective	Verb	Adverb
weigh	No	No	Yes	No
heft	Yes	No	Yes	No

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

weigh (noun)	heft (noun)
	the property of being large in mass

weigh (verb)	heft (verb)
show consideration for; take into account	lift or elevate
determine the weight of	test the weight of something by lifting it
have a certain weight
have weight; have import, carry weight
to be oppressive or burdensome