on the sly
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, 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.