perfidious
I
adjective
base, betraying, cheating, conniving, corrupt, deceitful, deceiving, designing, dishonest, dishonorable, disloyal, disobedient, dissembling, double-crossing, double-dealing, faithless, false, falsehearted, fraudulent, guileful, hypocritical, inconstant, insidious, intriguing, knavish, lying, perfidiosus, perfidus, perjured, plotting, scheming, shifty, slippery, sneaking, sneaky, traitorous, treacherous, treasonable, treasonous, tricky, trothless, unconscionable, undependable, unfaithful, unprincipled, unreliable, unscrupulous, untrue, untrustworthy, untruthful, without honor
II
index
bad (offensive), collusive, contemptible, dishonest, disingenuous, disobedient, evasive, faithless, false (disloyal), felonious, fraudulent, insidious, irresponsible, lying, machiavellian, malevolent, mendacious, outrageous, recreant, tortuous (corrupt), undependable, unreliable, unscrupulous, untrue, untrustworthy
Burton's Legal Thesaurus.
William C. Burton.
2006