1. a decision made without careful consideration, planning, or regard for consequences
Quitting his job was a thoughtless decision that he later regretted.
Sair do emprego foi uma decisão impensada que ele depois lamentou.
2. a choice made without adequate reflection on potential outcomes
The thoughtless decision to spend all their savings on a vacation left them in financial trouble.
A decisão impensada de gastar todas as economias em férias os deixou em dificuldades financeiras.