Mix up costume with lace fringes (6)
I believe the answer is:
garble
'mix up' is the definition.
(I've seen this in another clue)
'costume with lace fringes' is the wordplay.
'costume' becomes 'garb' (I've seen this in another clue).
'with' means one lot of letters go next to another.
'lace fringes' becomes 'le' (I am not sure about this - if you are sure you should believe this answer much more).
'garb'+'le'='GARBLE'
Can you help me to learn more?
(Other definitions for garble that I've seen before include "Distort (message)" , "Transmit in distorted version" , "distorted transmission" , "Indistinct speech" , "Corrupt" .)