Idjit
From Super-wiki
Look after your brother, ya idjit.
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"Idjit" is an affectionate, but exasperated, appellation applied by Bobby to Sam and Dean - first heard in 3.03 Bad Day At Black Rock. It has become something of a catch phrase, and Bobby's use of it is imitated by Crowley in 6.04 Weekend At Bobby's.
Jim Beaver refers to the followers of his Twitter as "Twidjits".