{With defiled, that is unwashen hands} (koinais chersin,
tout' estin aniptois). Associative instrumental case. Originally
koinos meant what was common to everybody like the _Koin(825f)
Greek. But in later Greek it came also to mean as here what is
vulgar or profane. So Peter in  Ac 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.