shackle vs fetter

shackle and fetter both are nouns.

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

As nouns, fetter is a hyponym of shackle; that is, fetter is a word with a more specific, narrower meaning than shackle:

shackle: a restraint that confines or restricts freedom (especially something used to tie down or restrain a prisoner)
fetter: a shackle for the ankles or feet

Other hyponyms of shackle include ball and chain, hobble, cuff, handcuff, handlock, manacle, chains, irons.

As verbs, shackle and fetter are synonyms defined as:

shackle (noun)	fetter (noun)
a restraint that confines or restricts freedom (especially something used to tie down or restrain a prisoner)	a shackle for the ankles or feet
a U-shaped bar; the open end can be passed through chain links and closed with a bar

shackle (verb)	fetter (verb)
restrain with fetters	restrain with fetters
bind the arms of