violent; hasty; rash
Over the months, as I found more and more things that were wrong with the house, I gradually realized that my decision to buy it had been an impetuous one.
in (into, in, on, upon)#petere (to go to, aim for, rush at) (Latin)
sounds like impatient, an impatient person will be impetuous im (not)-pet-tuo (to)-us. a dog which is not our pet will be very VIOLENT and RASH. im+petu => i am petu (in hindi which means who eats a lot), so if you don't give me enough food, i'll get violent, harsh, rough etc.