impound vs constrain

impound and constrain both are verbs.

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

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

impound: place or shut up in a pound
constrain: to close within bounds, or otherwise limit or deprive of free movement

Other hypernyms of impound include confine, hold, restrain.

impound (verb)	constrain (verb)
place or shut up in a pound	severely restrict in scope or extent
take temporary possession of as a security, by legal authority	to close within bounds, or otherwise limit or deprive of free movement
	compel to behave in a certain way