Out-of-character Definition

adjective

(idiomatic) Inconsistent with one's personality, disposition, or usual expected behaviour.

The burst of anger was out of character for the normally placid boy.

Wiktionary

(idiomatic, drama) Not in character; not successfully performing within the mindset of a given character in a theatrical performance. See also break character, drop character.

I was out of character for most of the first act because those people in the third row wouldn't stop chatting.

Wiktionary

(idiomatic, drama, role-playing games) Not acting; not "on"; behaving within one's natural personality rather than that of a character, or taking actions entirely outside the fictional context.

After watching him perform so energetically, it is a bit of a trip to hang out with him when he's out of character. In real life, he's really mellow.

Susan asked the GM, out of character, whether she was able to sense magic in the room.

Wiktionary

adverb

(idiomatic) In a manner inconsistent with one's usual and expected personality or behavior.

Wiktionary

(idiomatic, drama, role-playing games) Away from the mindset, personality, or behavior assumed for a role that an actor is rehearsing or performing, or that a player is playing.

He has the uncanny ability of getting in and out of character within a split second.

The comedian stepped out of character to mug directly to the audience.

Wiktionary