n. an impaired ability to direct or regulate ovolition, emotion, behavior, or cognition, or some other area, which often entails inability to resist impulses and leads to abnormal behaviors without significant provocation.
n. the number that when multiplied by another number gives a result of 1. The reciprocal of x is therefore 1/x and that of 1/x is x. So, for example, 1/4 is the reciprocal of 4.