noun
person with a dual personality
Refers to someone who exhibits two distinct personalities, often in a psychological or figurative sense.
彼は二重人格者だと言われている。
He is said to be a person with a dual personality.
二重人格 is the condition of dual personality itself, while 二重人格者 refers to the person who has that condition.
Compound of 二重 (double) + 人格 (personality) + 者 (person).