mid-15c., "pertaining to a political subject" (now obsolete), from L.L. subjectivus, from subjectus (see subject (n.)). Meaning "existing in the mind" (mind="the thinking subject") is from 1707; thus, "personal idiosyncratic" (1767). Related: Subjectively.
early 14c., "person under control or dominion of another," from O.Fr. suget, subget "a subject person or thing" (12c.), from L.subjectus, noun use of pp. of subicere "to place under," from sub "under" + combining form of jacere "to throw" (see jet (v.)). In 14c., sugges, sogetis, subgit, sugette; form re-Latinized in English 16c. Meaning "person or thing that may be acted upon" is recorded from 1590s. Meaning "subject matter of an art or science" is attested from 1540s, probably short for subject matter (late 14c.), which is from M.L. subjecta materia, a loan translation of Gk. hypokeimene hyle (Aristotle), lit. "that which lies beneath." Likewise some specific uses in logic and philosophy are borrowed directly from L. subjectum "foundation or subject of a proposition," a loan-translation of Aristotle's to hypokeimenon. Grammatical sense is recorded from 1630s. The adj. is attested from early 14c.