fetter vs constrain

fetter is a noun but constrain is not a noun.

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

As verbs, constrain is a hypernym of fetter; that is, constrain is a word with a broader meaning than fetter:

fetter: restrain with fetters
constrain: to close within bounds, or otherwise limit or deprive of free movement

Other hypernyms of fetter include confine, hold, restrain.

fetter (noun)	constrain (noun)
a shackle for the ankles or feet

fetter (verb)	constrain (verb)
restrain with fetters	severely restrict in scope or extent
	to close within bounds, or otherwise limit or deprive of free movement
	compel to behave in a certain way