Impulsivity: Inclined to act on impulse rather than thought. People who are overly impulsive, seem unable to curb their immediate reactions or think before they act. As a result, they may blurt out answers to questions or inappropriate comments, or run into the street without looking. Their impulsivity may make it hard for a child to wait for things they want or to take their turn in games. They may grab a toy from another child or hit when they are upset.