subjectivity vs subjective

subjectivity is a noun but subjective is not a noun.

Word	Noun	Adjective	Verb	Adverb
subjectivity	Yes	No	No	No
subjective	No	Yes	No	No

subjectivity (noun)	subjective (noun)
judgment based on individual personal impressions and feelings and opinions rather than external facts

subjectivity (adjective)	subjective (adjective)
	taking place within the mind and modified by individual bias
	of a mental act performed entirely within the mind