Coming just before Christmas (6)
I believe the answer is:
advent
I believe this is a double definition.
'coming' is the first definition.
(advent is the arrival or coming of something)
'before christmas' is the second definition.
(I've seen this before)
'just' acts as a link.
(Other definitions for advent that I've seen before include "Period in the Christian calendar" , "Coming, arrival" , "Period before Christmas" , "The coming of a religous period?" , "It's a-coming in December!" .)