liven up vs pep up

liven up and pep up both are verbs.

Word	Noun	Adjective	Verb	Adverb
liven up	No	No	Yes	No
pep up	No	No	Yes	No

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

Other hyponyms of liven up include ginger up, jazz up, juice up, inspirit, spirit, spirit up.

liven up (verb)	pep up (verb)
make lively	make more interesting or lively
	spur on or encourage especially by cheers and shouts