noun
individualist
Refers to someone who values personal independence and self-reliance, often in contrast to collectivism. Can be neutral or positive.
彼は個人主義者で、自分の信念に従って行動する。
He is an individualist and acts according to his own beliefs.
noun
egoist; selfish person
Often used in a negative sense for someone who prioritizes their own interests over others. Compare with 利己主義者, which is a more direct term for egoist.
See also: 利己主義者
あの人は個人主義者で、他人のことを考えない。
That person is an egoist and doesn't think about others.