constrain vs tighten

constrain and tighten both are verbs.

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

As verbs, constrain and tighten are synonyms defined as:

Other synonyms of constrain include stiffen, tighten up.

constrain (verb)	tighten (verb)
severely restrict in scope or extent	become tight or tighter
to close within bounds, or otherwise limit or deprive of free movement	make tight or tighter
compel to behave in a certain way	severely restrict in scope or extent
	narrow or limit