Antonyms for the word "un-premeditated" include "deliberate," "intentional," "calculated," "pre-planned," and "premeditated." These terms imply a level of forethought and planning that is absent in un-premeditated actions. When something is un-premeditated, it is done without prior consideration or planning, perhaps on impulse or by accident. In contrast, deliberate actions are carefully thought out and planned in advance, while intentional actions are done with a specific purpose or goal in mind. Similarly, calculated actions are based on careful consideration and planning, while pre-planned and premeditated actions indicate an even greater degree of forethought and preparation.