Appearance of naked elf (3)
I believe the answer is:
air
'appearance' is the definition.
(I've seen this before)
'naked elf' is the wordplay.
'naked' says to take the centre.
'elf' becomes 'fairy'.
The centre of 'fairy' is 'AIR'.
'of' acts as a link.
(Other definitions for air that I've seen before include "show" , "Refrain" , "Publish" , "14" , "Carriage" .)