One making a great show, on the pull at Christmas? (6)
I believe the answer is:
dasher
This clue is a double definition.
'one making a great show' is the first definition.
(dasher can mean a flamboyant person)
'on the pull at christmas?' is the second definition.
(reindeer pulling Santa's sleigh)
(Other definitions for dasher that I've seen before include "Haulier" , "Member of team pulling together" , "One going quickly" , "Fast runner" , "Spirited person" .)