The Greek adjective dolios (G1386) means deceitful, crafty, or guileful — the quality of one who uses dolos (bait/trap) to mislead others. It describes the character of false apostles who disguise themselves as servants of righteousness.
Dolios appears once in 2 Corinthians 11:13, where Paul describes false apostles as 'deceitful workers, masquerading as apostles of Christ.' The word connects to Satan himself (v.14), who 'masquerades as an angel of light.' This is crucial: deception is spiritually deadly precisely because it looks like truth. The dolios person does not announce themselves as false; they come dressed in gospel language while carrying a different spirit.