Antonyms for the word "not partial" can be "prejudiced," "biased," "one-sided," "unfair," "discriminatory," or "favoritist." When a person is "not partial," they are impartial, unbiased, or neutral. They do not show favoritism towards any particular person or group and treat everyone equally. "Not partial" individuals are fair, just, and objective in their actions and decisions. In contrast, a "partial" person shows a predisposition towards a particular party, individual, or group, which can lead to unfairness and discrimination. Therefore, being not partial is an important aspect of being a fair and just individual.