tighten vs strain

tighten is not a noun while strain is a noun.

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

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

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

tighten (noun)	strain (noun)
	an effortful attempt to attain a goal
	the act of singing
	an intense or violent exertion
	the general meaning or substance of an utterance
	a succession of notes forming a distinctive sequence
	a special variety of domesticated animals within a species
	(biology) a group of organisms within a species that differ in trivial ways from similar groups
	(physics) deformation of a physical body under the action of applied forces
	injury to a muscle (often caused by overuse); results in swelling and pain
	(psychology) nervousness resulting from mental stress
	difficulty that causes worry or emotional tension

tighten (verb)	strain (verb)
become tight or tighter	cause to be tense and uneasy or nervous or anxious
make tight or tighter	alter the shape of (something) by stress
severely restrict in scope or extent	to exert much effort or energy
narrow or limit	use to the utmost; exert vigorously or to full capacity
	remove by passing through a filter
	separate by passing through a sieve or other straining device to separate out coarser elements
	become stretched or tense or taut
	rub through a strainer or process in an electric blender
	test the limits of