The verbal prefix ter- in Malay is associated with three unrelated meanings: adjectival passive (be V-ed), accidental (happened to V) and abilitative (able to V). We argue that the prefix ter- has no independent semantic content, and the various interpretations of ter- result from ter- suppressing certain elements in the argument structure of the verb. Based on the behavior of the prefix ter, we propose a model of argument structure which allows us to modify the semantic roles within the thematic and the aspectual tiers of the argument structure. We propose that argument structure operations include the delinking of a semantic role (thematic and/or aspectual) from the argument. This delinking mechanism permits finer operations on arguments, resulting in a more articulated inventory of argument types.