sneak

Noun
  1. A person who is regarded as underhanded and furtive and contemptible (synset 110635564)
  2. Someone who prowls or sneaks about;
    Usually with unlawful intentions (synset 110506264)
  3. Someone acting as an informer or decoy for the police (synset 110110781)
Adjective
  1. Marked by quiet and caution and secrecy;
    Taking pains to avoid being observed (synset 302096119)
    "a furtive manner"; "a sneak attack"; "stealthy footsteps"; "a surreptitious glance at his watch"
Verb
  1. To go stealthily or furtively (synset 201915881)
    "..stead of sneaking around spying on the neighbor's house"
  2. Put, bring, or take in a secretive or furtive manner (synset 202603446)
    "sneak a look"; "sneak a cigarette"
  3. Make off with belongings of others (synset 202281711)
  4. Pass on stealthily (synset 202236110)
    "He slipped me the key when nobody was looking"

Other Searches