prepossession

1. A preconception or prejudice.
2. The state of being preoccupied with thoughts, opinions, or feelings.

noun

1. An inclination for or against that inhibits impartial judgment: bias, one-sidedness, partiality, partisanship, prejudice, tendentiousness. See affect/ineffectiveness, like/dislike, straight/bent.
2. Total occupation of the attention or of the mind: absorption, engrossment, enthrallment, immersion, preoccupation. See excite/bore/interest.

The noun has 2 meanings:

Meaning #1: the condition of being prepossessed

Meaning #2: an opinion formed beforehand without adequate evidence
  Synonyms: preconception, parti pris, preconceived opinion, preconceived idea, preconceived notion