θρησκός G2357
thrēskós · thrace'-kos · Adjective
probably from the base of θροέω; ceremonious in worship (as demonstrative), i.e. pious:--religious.
1 Occurrence in the King James Bible
James 1:26If any man among you seem to be religious, and bridleth not his tongue, but deceiveth his own heart, this man’s religion is vain.