1. A decision made based on intuition, instinct, or feeling rather than on careful analysis or rational thinking
I had to make a gut decision about which job offer to accept without having time to think it through.
Tive que tomar uma decisão por instinto sobre qual oferta de emprego aceitar sem ter tempo para pensar bem.
2. A choice based on one's immediate emotional or visceral reaction to a situation
My gut decision told me not to trust him, and I was right.
Meu instinto me disse para não confiar nele, e eu estava certo.