sly

• POS: Adjective, Noun

CIDE DICTIONARY

sly, a. [OE. sli, slegh, sleih, Icel. slgr, for slgr; akin to Sw. slug, Dan. slu, LG. slou, G. schlau; probably to E. slay, v.t.; cf. G. verschlagen sly. See Slay, v. t., and cf. Sleight.].

•  Dexterous in performing an action, so as to escape notice; nimble; skillful; cautious; shrewd; knowing; -- in a good sense.  [1913 Webster]

  "Be ye sly as serpents, and simple as doves."  [1913 Webster]

  "Whom graver age
  And long experience hath made wise and sly."  [1913 Webster]
•  Artfully cunning; secretly mischievous; wily.  [1913 Webster]

  "For my sly wiles and subtle craftiness,
  The litle of the kingdom I possess."  [1913 Webster]
•  Done with, and marked by, artful and dexterous secrecy; subtle; as, a sly trick.  [1913 Webster]

  "Envy works in a sly and imperceptible manner."  [1913 Webster]
•  Light or delicate; slight; thin.  [1913 Webster]

By the sly, or On the sly, in a sly or secret manner. [Colloq.] “Gazed on Hetty's charms by the sly.” G. Eliot. -- Sly goose (Zoöl.), the common sheldrake; -- so named from its craftiness.

Syn. -- Cunning; crafty; subtile; wily. See Cunning.

sly, adv. 

 Slyly.  Spenser.  [1913 Webster]

OXFORD DICTIONARY

sly, adj. (slyer, slyest)
1 cunning; crafty; wily.
2 a (of a person) practising secrecy or stealth. b (of an action etc.) done etc. in secret.
3 hypocritical; ironical.
4 knowing; arch; bantering; insinuating.
5 Austral. & NZ sl. (esp. of liquor) illicit.

Idiom

on the sly privately; covertly; without publicity (smuggled some through on the sly). sly dog colloq. a person who is discreet about mistakes or pleasures.

Derivative

slyly adv. (also slily). slyness n.

Etymology

ME sleh etc. f. ON sloegr cunning, orig. 'able to strike' f. sl{oacute}g- past stem of sl{aacute} strike: cf. SLEIGHT

THESAURUS

sly

Byzantine, Machiavellian, Machiavellic, acute, adroit, arch, artful, astute, back-door, backstairs, cagey, calculating, canny, clandestine, clever, covert, crafty, creep, crooked, cunning, cute, deceitful, deep, deep-laid, designing, devious, dexterous, diplomatic, dishonest, disingenuous, downy, feline, foxy, furtive, guileful, gumshoe, hidlings, hole-and-corner, hugger-mugger, ingenious, insidious, inventive, knowing, lurk, masterful, pawky, politic, predatory, privy, quiet, ready, resourceful, scheming, serpentine, shady, sharp, shifty, shrewd, skulk, skulking, slick, slide, slim, slink, slinking, slinky, slippery, smart, smooth, snake, snaky, sneaking, sneaky, snook, sophistical, steal, stealthy, strategic, subtile, subtle, supple, surreptitious, tactical, trickish, tricksy, tricky, under-the-counter, under-the-table, undercover, underground, underhand, underhanded, unfrank, unobtrusive, unscrupulous, vulpine, wary, wily

ROGET THESAURUS

sly

Cunning

N cunning, craft, cunningness, craftiness, subtlety, artificiality, maneuvering, temporization, circumvention, chicane, chicanery, sharp practice, knavery, jugglery, concealment, guile, doubling, duplicity, foul play, diplomacy, politics, Machiavelism, jobbery, backstairs influence, art, artifice, device, machination, plot, maneuver, stratagem, dodge, sidestep, artful dodge, wile, trick, trickery, ruse, ruse de guerre, finesse, side blow, thin end of the wedge, shift, go by, subterfuge, evasion, white lie, juggle, tour de force, tricks of the trade, tricks upon travelers, espieglerie, net, trap, Ulysses, Machiavel, sly boots, fox, reynard, Scotchman, Jew, Yankee, intriguer, intrigant, floater, Indian giver, keener, repeater, cunning, crafty, artful, skillful, subtle, feline, vulpine, cunning as a fox, cunning as a serpent, deep, deep laid, profound, designing, contriving, intriguing, strategic, diplomatic, politic, Machiavelian, timeserving, artificial, tricky, tricksy, wily, sly, slim, insidious, stealthy, underhand, subdolous, deceitful, slippery as an eel, evasive, crooked, arch, pawky, shrewd, acute, sharp, sharp as a tack, sharp as a needle, canny, astute, leery, knowing, up to snuff, too clever by half, not to be caught with chaff, tactful, diplomatic, politic, polite, cunningly, slyly, slily, on the sly, by a side wind, diamond cut diamond, a' bis ou a blanc, fin contre fin, something is rotten in the state of Denmark.

Concealment

N concealment, hiding, occultation, mystification, seal of secrecy, screen, disguise, masquerade, masked battery, hiding place, cryptography, steganography, freemasonry, stealth, stealthiness, sneakiness, obreption, slyness, latitancy, latitation, seclusion, privacy, secrecy, secretness, incognita, reticence, reserve, mental reserve, reservation, arriere pensee, suppression, evasion, white lie, misprision, silence, suppression of truth, underhand dealing, closeness, secretiveness, mystery, latency, snake in the grass, secret, stowaway, concealed, hidden, secret, recondite, mystic, cabalistic, occult, dark, cryptic, cryptical, private, privy, in petto, auricular, clandestine, close, inviolate, tortuous, behind a screen, undercover, under an eclipse, in ambush, in hiding, in disguise, in a cloud, in a fog, in a mist, in a haze, in a dark corner, in the shade, in the dark, clouded, wrapped in clouds, wrapt in clouds, invisible, buried, underground, perdu, secluded, undisclosed &c, untold, covert, untraceable, mysterious, irrevealable, inviolable, confidential, esoteric, not to be spoken of, unmentionable, obreptitious, furtive, stealthy, feline, skulking, surreptitious, underhand, hole and corner, sly, secretive, evasive, reserved, reticent, uncommunicative, buttoned up, close, close as wax, taciturn, secretly, in secret, in private, in one's sleeve, in holes and corners, in the dark, januis clausis, with closed doors, a huis clos, hugger mugger, a la derobee, under the cloak of, under the rose, under the table, sub rosa, en tapinois, in the background, aside, on the sly, with bated breath, sotto voce, in a whisper, without beat of drum, a la sourdine, behind the veil, beyond mortal ken, beyond the grave, beyond the veil, hid from mortal vision, into the eternal secret, into the realms supersensible, into the supreme mystery, in confidence, in strict confidence, in strictest confidence, confidentially, between ourselves, between you and me, between you and me and the bedpost, entre nous, inter nos, under the seal of secrecy, a couvert, underhand, by stealth, like a thief in the night, stealthily, behind the scenes, behind the curtain, behind one's back, behind a screen, incognito, in camera, it must go no further, it will go no further, don't tell a soul, tell it not in Gath, nobody the wiser, alitur vitium vivitque tegendo, let it be tenable in your silence still, background information, deep background information, deep background, background session, backgrounder, not for attribution.