aberrant behavior
aberrant behavior (a-ber-[schwa]nt). A single act of unplanned or thoughtless criminal behavior. • Many courts have held that aberrant behavior justifies a downward departure — that is, a more lenient sentence — under the federal sentencing guidelines, based on a comment in the introduction to the Guidelines Manual to the effect that the guidelines do not deal with single acts of aberrant behavior. U.S. Sentencing Guidelines Manual ch. 1, pt. A, ¶ 4.