pitilessness vs ruthlessness

pitilessness and ruthlessness both are nouns.

Word	Noun	Adjective	Verb	Adverb
pitilessness	Yes	No	No	No
ruthlessness	Yes	No	No	No

As nouns, pitilessness and ruthlessness are synonyms defined as:

pitilessness and ruthlessness: mercilessness characterized by a lack of pity

As nouns, pitilessness and ruthlessness are synonyms defined as:

Other synonyms of pitilessness include cruelty, mercilessness.

pitilessness (noun)	ruthlessness (noun)
mercilessness characterized by a lack of pity	mercilessness characterized by a lack of pity
feelings of extreme heartlessness	feelings of extreme heartlessness