tighten vs narrow

tighten is not a noun while narrow is a noun.

Word	Noun	Adjective	Verb	Adverb
tighten	No	No	Yes	No
narrow	Yes	Yes	Yes	No

As verbs, narrow is a hyponym of tighten; that is, narrow is a word with a more specific, narrower meaning than tighten:

Other hyponyms of tighten include constrict, constringe, firm, tauten, compact, compress, constrict, contract, press, squeeze, strain, tense.

tighten (noun)	narrow (noun)
	a narrow strait connecting two bodies of water

tighten (adjective)	narrow (adjective)
	not wide
	very limited in degree
	lacking tolerance or flexibility or breadth of view
	characterized by painstaking care and detailed examination
	limited in extent or scope

tighten (verb)	narrow (verb)
become tight or tighter	make or become more narrow or restricted
make tight or tighter	become tight or as if tight
severely restrict in scope or extent	become more focused on an area of activity or field of study
narrow or limit	define clearly