1. to lose the ability or capacity to do something; to transition from being able to being unable
After the accident, he became unable to walk without assistance.
Depois do acidente, ele ficou incapaz de caminhar sem assistência.
2. to lose one's capability due to illness, injury, age, or other circumstances
She became unable to continue working due to her health condition.
Ela ficou incapaz de continuar trabalhando devido à sua condição de saúde.