That would be unneighborly, and to this fella, unneighborliness is downright unAmerican.    From Wordnik.com.  ["An act of adultery between the defendant and the spouse of the plaintiff..."] Reference

There's an occasional upset, but for the most part, the treatment plant under construction, with the odor measures in place, are counteracting the nuisance and the unneighborliness that we had in the past, given the Greenpoint community.    From Wordnik.com.  [Inside the Smelly, Beautiful Eggs of Greenpoint] Reference

Nor did it make his defeat any more palatable to Cass that he had brought it on himself by his bad-tempered unneighborliness and by his overreaching disposition.    From Wordnik.com.  [Crooked Trails and Straight] Reference

I say “likely” rather than “certainly” because one can imagine unneighborliness on the other guy’s part that might be adequate to justify such a response, or for that matter cheerful acceptance of the sign by the other guy as part of the neighbors’ continued good-humored debate on the subject; but that’s all highly hypothetical since, as I said, I doubt that there was actually such a real sign.    From Wordnik.com.  [The Volokh Conspiracy » 2009 » October] Reference