Skins reversed to show nap (5)
I believe the answer is:
sleep
'nap' is the definition.
(synonyms)
'skins reversed' is the wordplay.
'skins' becomes 'peels' ('peel' can be a synonym of 'skin').
'reversed' says the letters should be written in reverse.
'peels' reversed gives 'SLEEP'.
'to show' acts as a link.
(Other definitions for sleep that I've seen before include "Snooze" , "Be dormant" , "''... that knits up the ravell'd sleeve of care'' (Macbeth)" , "crash" , "Doze, nap" .)