1. A severe, overwhelming, or catastrophic loss in a battle, competition, or conflict
The team suffered a disastrous defeat in the final match.
O time sofreu uma derrota desastrosa na partida final.
2. A humiliating or ruinous setback with serious consequences
The company faced a disastrous defeat in the market competition.
A empresa enfrentou uma derrota desastrosa na competição de mercado.