The term "being predisposed" implies a natural inclination or tendency towards a specific behaviour or state due to genetic or environmental factors. Its antonym would be "being impartial" or "being unbiased", which suggests a lack of inclination or preference towards a particular outcome. Another antonym could be "being obstinate" or "being inflexible," signifying a rigid adherence to one's beliefs regardless of external factors. Lastly, "being disinterested" could also act as an antonym for "being predisposed," which suggests a lack of interest or investment in a particular outcome or behaviour. These terms provide a contrast to the idea of being bound to specific behaviours or states and highlight the importance of being objective in decision-making.