/ ˈherəsi; NAmE / noun [ U , C ] ( pl. -ies )
1.
a belief or an opinion that is against the principles of a particular religion; the fact of holding such beliefs :
He was burned at the stake for heresy.
the heresies of the early Protestants
2.
a belief or an opinion that disagrees strongly with what most people believe :
The idea is heresy to most employees of the firm.
••
WORD ORIGIN
Middle English : from Old French heresie , based on Latin haeresis , from Greek hairesis choice (in ecclesiastical Greek heretical sect), from haireomai choose.