build up vs rearm

build up and rearm both are verbs.

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

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

Other hyponyms of build up include re-arm, forearm.

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