Definition of prepossesses:
(v) :
Chiefly followed by by or with: to preoccupy (someone) in an emotional or mental way, so as to preclude other things.
(v) :
(by extension) To cause (someone) to have a previous inclination against, for, or to something; to bias or prejudice; specifically, to induce in (someone) a favourable opinion beforehand, or at the outset.
(v) :
(obsolete) To cause (someone) to think a certain way.
(v) :
(obsolete) To occupy or possess (something) beforehand.
(v) :
(obsolete) (reflexive, chiefly passive voice) Chiefly followed by of or with: to cause (oneself) to obtain possession of something beforehand, or ahead of someone else.