smarten up vs groom

smarten up is not a noun while groom is a noun.

Word	Noun	Adjective	Verb	Adverb
smarten up	No	No	Yes	No
groom	Yes	No	Yes	No

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

Other hypernyms of smarten up include neaten.

smarten up (noun)	groom (noun)
	a man who has recently been married
	someone employed in a stable to take care of the horses
	a man participant in his own marriage ceremony

smarten up (verb)	groom (verb)
dress and groom with particular care, as for a special occasion	care for one's external appearance
make neat, smart, or trim	give a neat appearance to
	educate for a future role or function