See husband in Christmas show close to grim ghost (7)
I believe the answer is:
phantom
'ghost' is the definition.
(I know that ghost can be written as phantom)
'see husband in christmas show close to grim' is the wordplay.
'see husband' becomes 'h' (abbreviation).
'in' means one lot of letters goes inside another.
'christmas show' becomes 'panto' (short for pantomime - traditional Christmas show).
'close to' says to take the final letters (the close of something is the end).
The final letter of 'grim' is 'm'.
'h' inserted within 'panto' is 'phanto'.
'phanto'+'m'='PHANTOM'
(Other definitions for phantom that I've seen before include "Illusion (at the opera?)" , "Apparition, spectre" , "Ballet-dancing costume" , "Spirit" , "Blush" .)