Number of winks in a nap? (5)
I believe the answer is:
forty
'number of winks in a nap?' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for forty that I've seen before include "-- winks, a short sleep" , "Two-score" , "Two score" , "Kip" , "number of penitential days" .)