"duplicitous" in the adjective sense
1. ambidextrous, deceitful, double-dealing, duplicitous, Janus-faced, two-faced, double-faced, double-tongued
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
Source: WordNet® (An amazing lexical database of English)
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