A sumo wrestler's is called a mawashi (9)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
loincloth
(Other definitions for loincloth that I've seen before include "Garment Indian may have" , "this is placed round middle of groin?" , "Minimum clothing?" , "Simple garment" , "Minimal garment" .)