Paper-pale? (5,2,1,5)
I believe the answer is:
white as a sheet
'paper-pale?' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'paper-pale?' is the wordplay.
I cannot really see how this works, but
'paper' could be 'sheet' (sheet is a kind of paper) and 'sheet' is found within the answer.
'pale?' could be 'white' (pale in colour) and 'white' is found within the answer.
The remaining letters 'asa' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for white as a sheet that I've seen is " Very pale (simile)".)