I guess "disser" as in one who disses.
dis or diss (dĭs)
tr.v. dissed, diss·ing, diss·es Informal
To show disrespect to, often by insult or criticism: "[The network] is often dissed for going after older, less demographically desirable viewers" (Michael McWilliams).
[African American Vernacular English, short for disrespect.]
I have seen dis and diss but never disser.
