refresh vs freshen up

refresh and freshen up both are verbs.

Word	Noun	Adjective	Verb	Adverb
refresh	No	No	Yes	No
freshen up	No	No	Yes	No

As verbs, refresh and freshen up are synonyms defined as:

Other synonyms of refresh include freshen, refreshen.

refresh (verb)	freshen up (verb)
make fresh again	become or make oneself fresh again
become or make oneself fresh again	make brighter and prettier
make (to feel) fresh
refresh one's memory