The term "acting out" corresponds to Freud's use of the German word "agieren" (as a verb and as a noun). It should be distinguished from the closely related concept of "passageàl'acte," inherited from the French psychiatric tradition and denoting the impulsive and usually violent acts often addressed in criminology.

"Acting out" refers to the discharge by means of action, rather than by means of verbalization, of conflicted mental content.