An eccentric or odd person; someone unusual or quirky (can be humorous or pejorative).
あの研究者は風変わりで、周囲からは奇人と呼ばれている。
That researcher is eccentric and is called an oddball by those around him.
芸術家の中には奇人と評される人が少なくない。
There are quite a few artists who are described as eccentrics.
彼は町では奇人扱いされているが、仕事は非常に優秀だ。
He's treated as an oddball in town, but his work is excellent.