face up vs undertake

face up and undertake both are verbs.

Word	Noun	Adjective	Verb	Adverb
face up	No	No	Yes	No
undertake	No	No	Yes	No

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

Other hyponyms of face up include tackle, take on.

face up (verb)	undertake (verb)
deal with (something unpleasant) head on	promise to do or accomplish
	enter into a contractual arrangement
	enter upon an activity or enterprise
	accept as a charge
	accept as a challenge