imprisonment vs penalty

imprisonment and penalty both are nouns.

Word	Noun	Adjective	Verb	Adverb
imprisonment	Yes	No	No	No
penalty	Yes	No	No	No

As nouns, penalty is a hypernym of imprisonment; that is, penalty is a word with a broader meaning than imprisonment:

Other hypernyms of imprisonment include penalisation, penalization, punishment.

imprisonment (noun)	penalty (noun)
the act of confining someone in a prison (or as if in a prison)	the act of punishing, or the infliction of a penalty
putting someone in prison or in jail as lawful punishment	the disadvantage or painful consequences of an action or condition
the state of being imprisoned	(games) a handicap or disadvantage that is imposed on a competitor (or a team) for an infraction of the rules of the game
	a payment required for not fulfilling a contract