Word Study
treacherous
CIDE DICTIONARY
treacherous, a. [See Treacher.].
Like a traitor; involving treachery; violating allegiance or faith pledged; traitorous to the state or sovereign; perfidious in private life; betraying a trust; faithless. [1913 Webster]
"Loyal father of a treacherous son." [1913 Webster]
"The treacherous smile, a mask for secret hate." [1913 Webster]
Syn. -- Faithless; perfidious; traitorous; false; insidious; plotting.
OXFORD DICTIONARY
treacherous, adj.
1 guilty of or involving treachery.
2 (of the weather, ice, the memory, etc.) not to be relied on; likely to fail or give way.
1 guilty of or involving treachery.
2 (of the weather, ice, the memory, etc.) not to be relied on; likely to fail or give way.
Derivative
treacherously adv. treacherousness n.
Etymology
ME f. OF trecherous f. trecheor a cheat f. trechier, trichier: see TRICK
THESAURUS
treacherous
Machiavellian, Punic, ambidextrous, artful, calculating, chancy, chiseling, collusive, covinous, crafty, crooked, cunning, dangerous, deceitful, deceptive, desultory, dishonest, disloyal, double, double-crossing, double-dealing, double-faced, double-minded, double-tongued, doublehearted, doubtful, dubious, duplicitous, faithless, false, false-principled, falsehearted, finagling, fraudulent, furtive, guileful, hairy, hazardous, indirect, infirm, insecure, insidious, insubstantial, jeopardous, misleading, perfidious, perilous, precarious, precariousness, provisional, recreant, risky, rocky, scheming, shaky, sharp, shifting, shifty, slippery, sneaky, surreptitious, temporary, tentative, ticklish, tottery, traitorous, trickish, tricky, two-faced, uncertain, undependable, underhand, underhanded, unfaithful, unfaithworthy, unhealthy, unloyal, unpredictable, unreliable, unsafe, unsolid, unsound, unstable, unsteadfast, unsteady, unsubstantial, unsure, untrue, untrustworthy, wicked, wilyROGET THESAURUS
treacherous
Improbity
N improbity, dishonesty, dishonor, deviation from rectitude, disgrace, fraud, lying, bad faith, Punic faith, mala fides, Punica fides, infidelity, faithlessness, Judas kiss, betrayal, breach of promise, breach of trust, breach of faith, prodition, disloyalty, treason, high treason, apostasy, nonobservance, shabbiness, villainy, villany, baseness, abjection, debasement, turpitude, moral turpitude, laxity, trimming, shuffling, perfidy, perfidiousness, treachery, double dealing, unfairness, knavery, roguery, rascality, foul play, jobbing, jobbery, graft, bribery, venality, nepotism, corruption, job, shuffle, fishy transaction, barratry, sharp practice, heads I win tails you lose, mouth honor, dishonest, dishonorable, unconscientious, unscrupulous, fraudulent, knavish, disgraceful, wicked, false-hearted, disingenuous, unfair, one-sided, double, double- hearted, double-tongued, double-faced, timeserving, crooked, tortuous, insidious, Machiavelian, dark, slippery, fishy, perfidious, treacherous, perjured, infamous, arrant, foul, base, vile, ignominious, blackguard, contemptible, unrespectable, abject, mean, shabby, little, paltry, dirty, scurvy, scabby, sneaking, groveling, scrubby, rascally, pettifogging, beneath one, low-minded, low-thoughted, base-minded, undignified, indign, unbecoming, unbeseeming, unbefitting, derogatory, degrading, infra dignitatem, beneath one's dignity, ungentlemanly, ungentlemanlike, unknightly, unchivalric, unmanly, unhandsome, recreant, inglorious, corrupt, venal, debased, mongrel, faithless, of bad faith, false, unfaithful, disloyal, untrustworthy, trustless, trothless, lost to shame, dead to honor, barratrous, dishonestly, mala fide, like a thief in the night, by crooked paths, Int, O tempora!, O mores!, corruptissima respublica plurimae leges.For further exploring for "treacherous" in Webster Dictionary Online