Short snooze (3)
'short snooze' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nap that I've seen before include "Kip" , "A brief sleep, forty winks" , "Sleep - card game - fibres on a snooker table" , "A short day-sleep" , "Card game - quick sleep" .)
(Other definitions for catnap that I've seen before include "Forty winks (for moggy?)" , "little snooze" , "Short sleep" , "Drop off" , "For a rest" .)