Tearaway
Part of speech: noun
Definition: An impetuous and reckless person who is difficult to control; a hothead.
Impetuous
Part of speech: adjective
Definition: Making arbitrary decisions, esp. in an impulsive and forceful manner.Characterized by sudden and violent force.
Example sentence: When I first went to work... I had over me an impetuous, hustling man. It was necessary for me to be up to the top notch to give satisfaction. I worked faster than I otherwise would have done, and to him I attribute the impetus that I acquired.