Mark 7:2

With defiled, that is unwashen hands

(κοιναις χερσιν, τουτ' εστιν ανιπτοις). Associative instrumental case. Originally κοινος meant what was common to everybody like the Koine Greek. But in later Greek it came also to mean as here what is vulgar or profane. So Peter in Acts 10:14 "common and unclean." The next step was the ceremonially unclean. The emissaries of the Pharisees and the scribes from Jerusalem had seen "some of the disciples" eat without washing their hands, how many we are not told. Swete suggests that in going through the plain the disciples were seen eating some of the bread preserved in the twelve baskets the afternoon before across the lake. There was no particular opportunity to wash the hands, a very proper thing to do before eating for sanitary reasons. But the objection raised is on ceremonial, not sanitary, grounds.