7And as they continued to ask him, he stood up and said to them,“Let him who is without sin among you be the first to throw a stone at her.”
It doesn’t mean sinless. Nobody is sinless. No judge could pass sentence on a suspect if he ought to be “without sin.” Jesus means, “Be honest. Do you want to stone her yourself?” He is confronting them with their own motives.
7 And as they continued to ask him, he stood up and said to them, “Let him who is without sin among you be the first to throw a stone at her.”