In The Witch of Blackbird Pond, what is Matthew Wood's reaction to Kit?
I take it you are referring to when Kit arrives at her Aunt and Uncle's house without informing them that she was planning on staying with them for good. The answer to your question can be found in Chapter Three, that narrates Kit's surprise visit on the Wood household and the various reactions to this strange newcomer in this drab, Puritan world. Whilst the other members of the Wood family are pleased to see Kit and welcome her in, her Uncle, Matthew Wood, is shown to be less than pleased. Note how he is shown to respond to Kit's presence and her news that she will be staying with them:
Matthew Wood had not sat down at the table with the others. Though he had said nothing, Kit had been aware that not a motion had escaped his intent scowl.
Thus we can see that he is not happy about the new arrival, and this impression is confirmed when he leaves and stumbles across the trunks that Kit brought with her. Note how he asks about them "coldly."