There are two types of truncation that yield shortening of a morphological constituent, FAKE TRUNCATION (templatic) and TRUE TRUNCATION (a-templatic, subtractive). This article provides an analysis of true truncation in colloquial Hebrew imperatives. It is shown that true truncation cannot target a designated phonological unit, since in some forms CV is truncated and in others only V. In addition, there are cases where truncation is blocked. The framework of optimality theory adopted here allows a unified account of the data in terms of constraint interaction. It is argued that an antifaithfulness truncation constraint, which must be morphological, interacts with both faithfulness and markedness constraints. Truncation is minimized to one segment by a general antideletion faithfulness constraint, but markedness constraints may impose truncation of more than one segment. There are cases where truncation is blocked, which suggests that the truncation constraint is violable. The discussion includes regular and irregular verbs and instances of free variation.*.