1. A problem or matter that is not immediately obvious, requires careful attention to detect, and is often complex or delicate in nature
The subtle issue with the contract was buried in the fine print.
A questão sutil do contrato estava escondida nas letras miúdas.
2. A sensitive or nuanced problem that requires tact and careful handling
There's a subtle issue between the two departments that needs addressing.
Há uma questão sutil entre os dois departamentos que precisa ser resolvida.