Nominally Christmas (4)
I believe the answer is:
noel
'christmas' is the definition.
(Noel can mean Christmas)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for noel that I've seen before include "seasonal festival" , "Girl - boy - Christmas" , "Coward - Christmas" , "Festive season" , "Religious festival" .)