1. Actions or conduct that lack consideration, care, or reflection; behavior done without thinking about consequences or others' feelings
His thoughtless behavior at the meeting offended several colleagues.
Seu comportamento impensado na reunião ofendeu vários colegas.
2. Careless or inconsiderate actions that show a lack of concern for others
Leaving the dishes unwashed is thoughtless behavior that affects the whole household.
Deixar os pratos sujos é um comportamento impensado que afeta toda a casa.