compunction vs penance

compunction and penance both are nouns.

Word	Noun	Adjective	Verb	Adverb
compunction	Yes	No	No	No
penance	Yes	No	No	No

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

Other hyponyms of compunction include guilt, guilt feelings, guilt trip, guilty conscience, penitence, repentance.

compunction (noun)	penance (noun)
a feeling of deep regret (usually for some misdeed)	voluntary self-punishment in order to atone for some wrongdoing
	a Catholic sacrament; repentance and confession and atonement and absolution
	remorse for your past conduct