kit vs fit out

kit is a noun but fit out is not a noun.

Word	Noun	Adjective	Verb	Adverb
kit	Yes	No	Yes	No
fit out	No	No	Yes	No

As verbs, fit out is a hypernym of kit; that is, fit out is a word with a broader meaning than kit:

Other hypernyms of kit include equip, fit, outfit.

kit (noun)	fit out (noun)
young of any of various fur-bearing animals
gear consisting of a set of articles or tools for a specified purpose
a case for containing a set of articles

kit (verb)	fit out (verb)
supply with a set of articles or tools	provide with clothes or put clothes on
	provide with (something) usually for a specific purpose