1. In Law, this is why one committed the crime, the inducement, reason, or willful desire and purpose behind the commission of an offense. Whether the purpose was good, like helping someone commit suicide, or bad, like committing murder, it is not a deciding factor in deciding guilt or innocence. But, intent is. In a libel case, it has importance. It may be used by a defending attorney in punishment mitigation or by a prosecuting attorney as circumstantial evidence to prove guilt. 2. In Psychology, this is what energizes people to action and determines their choice of behavior, as concern, desire, emotion, or need.