1. In a way that is secret, stealthy, or done without being noticed; clandestinely
He surreptitiously slipped out of the meeting to avoid questions.
Ele saiu sorrateiramente da reunião para evitar perguntas.
2. Done or obtained by stealth or concealment; furtively
She surreptitiously took a photograph of the document.
Ela fotografou o documento sorrateiramente.