sneaks

verb

Moves stealthily and secretly, often to avoid detection while doing something illicit.

"He always sneaks extra biscuits when no one is looking."

noun

Individuals who behave in a secretive, underhand, or deceitful manner.

"Don't be one of those sneaks who gossip behind people's backs."

Thesaurus

Synonyms: pilfer, lift, swipe, abstract, purloin, filch, nobble, snarf, cabbage, pinch, hook, prowler