Noun

• S: (n) sneak (a person who is regarded as underhanded and furtive and contemptible)
• direct hypernym / inherited hypernym / sister term
• derivationally related form
• S: (n) prowler, sneak, stalker (someone who prowls or sneaks about; usually with unlawful intentions)
• direct hypernym / inherited hypernym / sister term
• derivationally related form
• S: (n) fink, snitch, snitcher, stoolpigeon, stool pigeon, stoolie, sneak, sneaker, canary (someone acting as an informer or decoy for the police)

Verb

• S: (v) sneak, mouse, creep, pussyfoot (to go stealthily or furtively) "..stead of sneaking around spying on the neighbor's house"
• S: (v) sneak (put, bring, or take in a secretive or furtive manner) "sneak a look"; "sneak a cigarette"
• S: (v) pilfer, cabbage, purloin, pinch, abstract, snarf, swipe, hook, sneak, filch, nobble, lift (make off with belongings of others)
• S: (v) slip, sneak (pass on stealthily) "He slipped me the key when nobody was looking"
• direct hypernym / inherited hypernym / sister term
• sentence frame

Adjective

• S: (adj) furtive, sneak, sneaky, stealthy, surreptitious (marked by quiet and caution and secrecy; taking pains to avoid being observed) "a furtive manner"; "a sneak attack"; "stealthy footsteps"; "a surreptitious glance at his watch"