The definition I was using was "1. to treat with disdain or contempt, especially by ignoring. 2. to check or reject with a sharp rebuke or remark." re. dictionary.com

I think all of my examples hit one or the other of these pretty clearly, but your mileage may vary. Regarding my use of the word "decline" and Emma's behavior to Robert Martin, it is my understanding that as a lady, and of superior rank, it was up to her to signal an introduction because of the general etiquette of the times. She undoubtedly knew this rule and "declined" through inaction.

I can't agree that the visit to the Martins was in keeping with custom, as Emma's own conscience told her it was wrong. Harriet and the Martins all showed discomfort with it, as it was acting ungratefully.

As for Elton, it is a less clear cut case, but she does let several things slip about how she feels about their respective status. "had I supposed that she were not your attraction to Hartfield, I should certainly have thought you judged ill in making your visits so frequent... In no other light could you have been more to me than a common acquaintance." To me, his subsequent behavior shows he was conscious of a snub, rather than just disappointed hopes.