imprisonment vs punishment

imprisonment and punishment both are nouns.

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

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

Other hypernyms of imprisonment include penalisation, penalization, penalty.

imprisonment (noun)	punishment (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 state of being imprisoned