impulsive

adjective

1. 1

   characterized by undue haste and lack of thought or deliberation

   a hotheaded decision

   liable to such impulsive acts as hugging strangers

2. 2

   determined by chance or impulse or whim rather than by necessity or reason

   a capricious refusal

   authoritarian rulers are frequently capricious

3. 3

   having the power of driving or impelling

   a driving personal ambition

   the driving force was his innate enthusiasm

4. 4

   without forethought

   letting him borrow her car was an impulsive act that she immediately regretted

5. 5

   proceeding from natural feeling or impulse without external stimulus

   an impulsive gesture of affection