penitence vs penance

penitence and penance both are nouns.

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

As nouns, penitence and penance are synonyms defined as:

Other synonyms of penitence include repentance.

penitence (noun)	penance (noun)
remorse for your past conduct	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