build up vs increase

build up is not a noun while increase is a noun.

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

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

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

build up (noun)	increase (noun)
	the act of increasing something
	the amount by which something increases
	a change resulting in an increase
	a process of becoming larger or longer or more numerous or more important
	a quantity that is added

build up (verb)	increase (verb)
form or accumulate steadily	become bigger or greater in amount
enlarge, develop, or increase by degrees or in stages	make bigger or more
change the use of and make available or usable
bolster or strengthen
prepare oneself for a military confrontation