pardon vs clemency

pardon and clemency both are nouns.

Word	Noun	Adjective	Verb	Adverb
pardon	Yes	No	Yes	No
clemency	Yes	No	No	No

As nouns, clemency is a hypernym of pardon; that is, clemency is a word with a broader meaning than pardon:

pardon: the formal act of liberating someone
clemency: leniency and compassion shown toward offenders by a person or agency charged with administering justice

Other hypernyms of pardon include mercifulness, mercy.

pardon (noun)	clemency (noun)
the act of excusing a mistake or offense	leniency and compassion shown toward offenders by a person or agency charged with administering justice
the formal act of liberating someone	good weather with comfortable temperatures
a warrant granting release from punishment for an offense

pardon (verb)	clemency (verb)
grant a pardon to
accept an excuse for