Synonyms:
- artful,
- back-door,
- backstairs,
- calculating,
- chiseling,
- clandestine,
- collusive,
- concealed,
- covert,
- covinous,
- crafty,
- cunning,
- deceitful,
- doggo,
- false,
- falsehearted,
- feline,
- finagling,
- fraudulent,
- furtive,
- guileful,
- hidden,
- hidden out,
- hidlings,
- hole-and-corner,
- hugger-mugger,
- hush-hush,
- in ambush,
- in hiding,
- in the wings,
- indirect,
- insidious,
- lurking,
- on the sly,
- on tiptoe,
- private,
- privy,
- prowling,
- pussyfoot,
- pussyfooted,
- quiet,
- scheming,
- secret,
- secretive,
- sharp,
- shifty,
- skulking,
- slinking,
- slinky,
- slippery,
- sly,
- sneaking,
- sneaky,
- stealing,
- stealthy,
- treacherous,
- trickish,
- tricky,
- two-faced,
- under cover,
- under-the-counter,
- under-the-table,
- undercover,
- underground,
- underhand,
- underhanded,
- unobtrusive,
- veiled,
- waiting concealed,
- wily