1) A 'buttery jumper' is slang for a homosexual male, originating in southern Birmingham - it is not in heavy mainstream use, but is rising in popularity.

2) When one simply makes a toastal mistake, rendering one's jumper slightly covered in butter or margarine.
"You see that guy, James, he has a 'buttery jumper'"
by Jim Ratcliffe October 30, 2007
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