wash up vs freshen

wash up and freshen both are verbs.

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

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

Other hypernyms of wash up include freshen up, refresh, refreshen.

wash up (verb)	freshen (verb)
wash one's face and hands	make fresh again
wear out completely	become or make oneself fresh again
be carried somewhere by water or as if by water	make (to feel) fresh
wash dishes
carry somewhere (of water or current or waves)