Type: Dark charm
Pronunciation: os-SCOW-zee
Description: Seal someone's mouth shut, making it appear it was never there.
Seen/Mentioned: Used by Leta Lestrange on a girl from Gryffindor when they were both in their third year at Hogwarts. The Gryffindor girl was speaking ill of Lestrange behind her back until Lestrange emerged from hiding nearby, and muted the Gryffindor girl with this spell.
Etymology: Possibly derived as a portmanteau of os, Latin for "mouth", and clausi (a conjugated form of claudo), Latin for "I shut". It may additionally be a pun or wordplay on scusi, the Italian interjection for "excuse me".
