A quality or way of life involving being exceedingly innocent in reality, but saying terribly sexually inappropriate things without realizing it in front of children.
Muellerist: "Alright, class, let's look up Leda and the Swan." Class: (dead silence) Muellerist: "Oh my, why are these so graphic?" Class: "What a muellerism!"--- Muellerist with a speech impediment in a Croc's store: "Goth, theeth cocs are tho comforthabul!" Friends: "Mueller!"