(1):

(a.) Especially, pertaining to, or derived from, one's own consciousness, in distinction from external observation; ralating to the mind, or intellectual world, in distinction from the outward or material excessively occupied with, or brooding over, one's own internal states.

(2):

(a.) Of or pertaining to a subject.

(3):

(a.) Modified by, or making prominent, the individuality of a writer or an artist; as, a subjective drama or painting; a subjective writer.