Pertaining to subjects as opposed to objects (A subject is one who perceives or is aware; an object is the thing perceived or the thing that the subject is aware of.)
Resulting from or pertaining to personal mindsets or experience, arising from perceptive mental conditions within the brain and not necessarily or directly from external stimuli.
(linguistics,grammar) Describing conjugation of a verb that indicates only the subject (agent), not indicating the object (patient) of the action. (In linguistic descriptions of Tundra Nenets, among others.)