free pardon vs mercifulness

free pardon and mercifulness both are nouns.

Word	Noun	Adjective	Verb	Adverb
free pardon	Yes	No	No	No
mercifulness	Yes	No	No	No

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

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

Other hypernyms of free pardon include clemency, mercy.

free pardon (noun)	mercifulness (noun)
the formal act of liberating someone	leniency and compassion shown toward offenders by a person or agency charged with administering justice
	a disposition to be kind and forgiving
	the feeling that motivates compassion