malignancy vs malignity

malignancy and malignity both are nouns.

Word	Noun	Adjective	Verb	Adverb
malignancy	Yes	No	No	No
malignity	Yes	No	No	No

As nouns, malignancy and malignity are synonyms defined as:

malignancy and malignity: quality of being disposed to evil; intense ill will

Other synonyms of malignancy include malignance.

malignancy (noun)	malignity (noun)
quality of being disposed to evil; intense ill will	quality of being disposed to evil; intense ill will
(medicine) a malignant state; progressive and resistant to treatment and tending to cause death	wishing evil to others