From medieval Latin impulsivus, ‘to impel to’ come and see Jo Brami (for example).
Who acts as if driven by an irresistible force to make you laugh: impulsive who can't stop talking (for an hour or so).
Synonyms:
Bouillant: he's a hothead, all right!
Emporté: when he talks about housework!
Fiery: after his experience in Cap d'Agde
Spontaneous: yes, there will be improvisation!
Volcanic: with the much too rich!
Opposites:
Calm - level-headed (everything he's not...)