someone acting as an informer or decoy for the police
- stoolpigeon - stool pigeon
someone who prowls or sneaks about
usually with unlawful intentions
a person who is regarded as underhanded and furtive and contemptible
pass on stealthily
"He slipped me the key when nobody was looking"
make off with belongings of others
put, bring, or take in a secretive or furtive manner
"sneak a look"
"sneak a cigarette"
to go stealthily or furtively
"..stead of sneaking around spying on the neighbor's house"
marked by quiet and caution and secrecy
taking pains to avoid being observed
"a furtive manner"
"a sneak attack"
"a surreptitious glance at his watch"