[1] : The Collaborative International Dictionary of English v.0.48

surreptitious \sur`repti"tious\, a. l. surreptitius, or
   subreptitius, fr. surripere, subripere, to snatch away, to
   withdraw privily; sub- under + rapere to snatch. see sub-,
   and ravish.
   done or made by stealth, or without proper authority; made or
   introduced fraudulently; clandestine; stealthy; as, a
   surreptitious passage in an old manuscript; a surreptitious
   removal of goods. -- sur`repti"tiously, adv.
   1913 webster
see also:
sub- ravish sur`repti"tiously 

[2] : WordNet (r) 2.0

surreptitious
     adj 1: marked by quiet and caution and secrecy; taking pains to
            avoid being observed; "a furtive manner"; "a lurking
            prowler"; "a sneak attack"; "stealthy footsteps"; "a
            surreptitious glance at his watch"; "someone skulking
            in the shadows" syn: furtive, lurking, skulking,
             sneaka, sneaky, stealthy
     2: conducted with or marked by hidden aims or methods;
        "clandestine intelligence operations"; "cloak-and-dagger
        activities behind enemy lines"; "hole-and-corner
        intrigue"; "secret missions"; "a secret agent"; "secret
        sales of arms"; "surreptitious mobilization of troops";
        "an undercover investigation"; "underground resistance"
        syn: clandestine, cloak-and-dagger, hole-and-cornera,
         hugger-mugger, hush-hush, on the quietp, secret,
         undercover, underground
see also:
furtive lurking skulking sneaka sneaky stealthy 
clandestine cloak-and-dagger hole-and-cornera hugger-mugger hush-hush 
on the quietp secret undercover underground 

[3] : Moby Thesaurus II by Grady Ward, 1.0

70 moby thesaurus words for "surreptitious":
   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

[4] : Bouvier's Law Dictionary, Revised 6th Ed (1856)

surreptitious. that which is done in a fraudulent stealthy manner. 

Surreptitious >> S Words
Surreptitious, definition of term: Surreptitious
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