1. to lose strength, power, or effectiveness toward the end of a process, competition, or period
The runner began to weaken in the final stages of the marathon.
O corredor começou a enfraquecer nas fases finais da maratona.
2. to become less effective or convincing in the conclusion of an argument, presentation, or effort
The team's defense started to weaken in the final stages of the match.
A defesa do time começou a enfraquecer nas fases finais do jogo.