Misinterpret clothing left loose at the back (6)
I believe the answer is:
garble
'misinterpret' is the definition.
(thesaurus)
'clothing left loose at the back' is the wordplay.
'clothing' becomes 'garb' (garb is a kind of clothing**).
'left' becomes 'l' (common abbreviation).
'at the back' indicates one should take the final letters.
The last letter of 'loose' is 'e'.
'garb'+'l'+'e'='GARBLE'
(Other definitions for garble that I've seen before include "Give confused account, hard to understand" , "Confuse (a message)" , "Distort (message)" , "distorted transmission" , "jumble" .)