This term generally indicates any behavior of beings that may bring about a subsequent effect. Such behavior is subdivided into three kinds: corporal, verbal, and mental. The subdivision corresponds with the behaviors of the body, of speech, and of thought. They can all produce results: good, bad, or something in between. Therefore, concerning their value, one can distinguish wholesome action, evil action, and also those which cannot bring about the wholesome or the unwholesome. In the idea of the reincarnation in Buddhism, behavior in a previous life determines the form of existence in a later world. Because of this, no matter whether one has deliverance as one’s goal or not, in order to obtain a result hoped, it is extremely important to control one’s three actions: corporal, verbal, and mental.
Learned and noble disciples can no longer perform corporal, verbal, or mental action, and will not go to the three evil destinations. Even if they may be heedless, noble disciples are decidedly turned to sambodhi (perfect enlightenment), so they go to the human world and the heaven in the seven existences, and reach the end of suffering. (Miscellaneous Canonical Texts)