An internet forum troll of Irish descent with a particular penchant for baiting moderators.
Best known for 1 liners and smilies, a zehner will one minute be your friend, the next stab you in the back. A zehner is bad.
zehner can also be used as a verb.
verb: to zehner...Don't zehner the forum you Irish prick.
noun: He's a right tossing zehner, should be banned.