偷 (tōu): to steal; stealthily

Yesterday on the bus, a thief took advantage of my inattention and stole my wallet.

Mom noticed a piece of cake was missing from the fridge; it turned out that my younger brother had secretly eaten it while everyone was asleep.

That employee was taken away by the police for stealing company money and is still under investigation.

Peeking at others' answers during an exam is a sign of dishonesty; once discovered, you will face disciplinary action.

He pretended to be reading in the library, but actually he was eavesdropping on the conversation between two people nearby.