December number (4)
I believe the answer is:
noel
'december number' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for noel that I've seen before include "Girl - boy - Christmas" , "A lone French Christmas" , "namely 4 [COWARD]" , "Coward for one" , "A lone sort of Christmas" .)