1. (

• impulsive ,
• unprompted

) proceeding from natural feeling or impulse without external stimulus; "an impulsive gesture of affection" ;

2. (

• impulsive

) without forethought; "letting him borrow her car was an impulsive act that she immediately regretted" ;

3. (

• driving ,
• impulsive

) having the power of driving or impelling; "a driving personal ambition"; "the driving force was his innate enthusiasm"; "an impulsive force" ;

4. (

• capricious ,
• impulsive ,
• whimsical

) determined by chance or impulse or whim rather than by necessity or reason; "a capricious refusal"; "authoritarian rulers are frequently capricious"; "the victim of whimsical persecutions" ;

5. (

• hotheaded ,
• impulsive ,
• impetuous ,
• madcap ,
• tearaway ,
• brainish

) characterized by undue haste and lack of thought or deliberation; "a hotheaded decision"; "liable to such impulsive acts as hugging strangers"; "an impetuous display of spending and gambling"; "madcap escapades"; (`brainish' is archaic) ;