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.

[Blacks Law 8th]