build up vs ameliorate

build up and ameliorate both are verbs.

Word	Noun	Adjective	Verb	Adverb
build up	No	No	Yes	No
ameliorate	No	No	Yes	No

As verbs, ameliorate is a hypernym of build up; that is, ameliorate is a word with a broader meaning than build up:

Other hypernyms of build up include amend, better, improve, meliorate.

build up (verb)	ameliorate (verb)
form or accumulate steadily	get better
enlarge, develop, or increase by degrees or in stages	to make better
change the use of and make available or usable
bolster or strengthen
prepare oneself for a military confrontation