1. 
[syn: ambidextrous, deceitful, double-dealing, duplicitous, Janus-faced, two-faced, double-faced, double-tongued]
The Collaborative International Dictionary of English v.0.48:
duplicitous \du*plic"i*tous\ adj.
   exhibiting duplicity[2]; deceitful; double-dealing.
   Syn: ambidextrous, deceitful, double-dealing, two-faced.
        [WordNet 1.5]
WordNet (r) 3.0 (2006):
duplicitous
    adj 1: marked by deliberate deceptiveness especially by
           pretending one set of feelings and acting under the
           influence of another; "she was a deceitful scheming
           little thing"- Israel Zangwill; "a double-dealing double
           agent"; "a double-faced infernal traitor and schemer"-
           W.M.Thackeray [syn: ambidextrous, deceitful, double-
           dealing, duplicitous, Janus-faced, two-faced,
           double-faced, double-tongued]