In improvisational theater attitude can have several meanings.
An attitude, a personal opinion, or a feeling about something: a personal one or the one of the character one plays on stage,
a conviction, a basic conviction targeting a specific goal - again the personal one and the one of the character on the stage.
a physical posture, not only the temporary but also the fundamental position of the human body.
It can be helpful for a scene to enter the stage with a particular posture.