fetter vs restrain

fetter is a noun but restrain is not a noun.

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

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

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

Other hypernyms of fetter include confine, constrain, hold.

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

fetter (verb)	restrain (verb)
restrain with fetters	prevent the action or expression of
	to close within bounds, or otherwise limit or deprive of free movement
	restrict (someone or something) so as to make free movement difficult
	prevent (someone or something) from doing something