Yearn to have little old Christmas show (5)
I believe the answer is:
panto
'christmas show' is the definition.
(short for pantomime - traditional Christmas show)
'yearn to have little old' is the wordplay.
'yearn' becomes 'pant' (to pant for something is to yearn for or crave it).
'to have' is a charade indicator (letters next to each other).
'little' indicates taking the first letters.
The initial letter of 'old' is 'o'.
'pant'+'o'='PANTO'
(Other definitions for panto that I've seen before include "Trad. Christmas fun (abbr.)" , "Fun for kids" , "Dick Whittington" , "Cinderella or Puss in Boots, say?" , "Christmas entertainment (abbr.)" .)