1. (noun)(Geocaching) A non-geocacher, especially one from whom geocaching activities must be concealed.
2. (verb)The vandalization of a geocache by a muggle.
"Could not find the cache, it may have been muggled."
2) Another name for a Squib.
2) Argus Filch has no magic, and is born from a pure blood family (he's a squib), so he can be referred to as either a muggle or a squib.