Frame this, with wits! (4)
I believe the answer is:
sash
'frame' is the definition.
(I know that sash is a type of frame)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for sash that I've seen before include "Decorative belt" , "Frame for a windowpane" , "Band - scarf" , "Ribbon worn over the shoulder" , "Brown bread for waist or shoulder" .)