Synonyms for Deceitful (same or very similar meaning)
WordNet sense 1 (intended to deceive):
fallacious, fraudulent
WordNet sense 2 (marked by deliberate deceptiveness especially by pretending one set of feelings and acting under the influence of another):
ambidextrous, double-dealing, duplicitous, two-faced, double-faced, double-tongued, Janus-faced
From the ODE community, based on WordNet
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