duplicitous
doo-PLIS-ih-tusadjMeaning two-faced; saying one thing and doing another
Memory hook DUPLI-citous: a DUPLICATE face. Rex smiles at the queen, “I’m your loyal knight!”, then turns around and whispers plans to the dragon. Two faces, like a duplicate: he is duplicitous.
The duplicitous spy smiled at both sides while secretly working for neither.
In context The knight seemed loyal to the king, but he was duplicitous: by day he guarded the castle, and by night he sent messages to the king’s enemies.
Similar double-dealing, two-faced, deceitful, treacherous
Opposite honest, sincere, aboveboard
From duplicity, Latin duplicitas, “doubleness,” from duplex, double.