1. To fall behind or lose momentum near the end of a race, competition, or task
The runner started strong but began to lag at the finish line.
O corredor começou forte, mas começou a ficar para trás na reta final.
2. To weaken or slow down in performance when approaching completion
The team lagged at the finish of the championship game.
O time desacelerou no final do jogo do campeonato.