|Well, congrats. You discovered it. You get to name it.|
Although this article is based on canonical information, the actual name of this subject is conjectural.
The repelling spell was a simple spell that was used to repel anything near the caster telekinetically.
Rowena later used it to send Sam Winchester flying away from her.
Boyd Loughlin used the spell to fling Sam across the room.
The user would wave their arms to the side and recite the Latin incantation "Abite!" (later simplified to "Abi!"). Anything in the path would be pushed back.