1. An indication or evidence that suggests a positive outlook or confidence about future outcomes
The stock market recovery is a sign of optimism about the economy.
A recuperação do mercado de ações é um sinal de otimismo sobre a economia.
2. A gesture, statement, or action that demonstrates hopefulness or positive expectations
His decision to invest in the project is a clear sign of optimism.
Sua decisão de investir no projeto é um claro sinal de otimismo.