Item of attire in the window? (4)
I believe the answer is:
sash
'window?' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for sash that I've seen before include "Waistband - type of window" , "Sliding window frame" , "Item of clothing - frame for glass" , "Type of sliding window" , "Brown bread for waist or shoulder" .)