Great Swiss hero wearing short Indian garment (7)
I believe the answer is:
stellar
'great' is the definition.
(I've seen this in another clue)
'swiss hero wearing short indian garment' is the wordplay.
'swiss hero' becomes 'Tell' (folk hero William Tell).
'wearing' is an insertion indicator.
'short' means to remove the last letter.
'indian garment' becomes 'sari' (I've seen this in another clue).
'sari' with its last letter removed is 'sar'.
'tell' going within 'sar' is 'STELLAR'.
(Other definitions for stellar that I've seen before include "High-class" , "like a star" , "boss!" , "Astral" , "Like highlights" .)