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.