build up vs ramp up

build up and ramp up both are verbs.

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

As verbs, build up and ramp up are synonyms defined as:

Other synonyms of build up include build, work up.

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