Stars fighting inside furniture shop (6)
I believe the answer is:
dwarfs
'stars' is the definition.
(white dwarfs etc)
'fighting inside furniture shop' is the wordplay.
'fighting' becomes 'war'.
'inside' means one lot of letters goes inside another.
'furniture shop' becomes 'DFS' (UK furniture shop).
'war' placed inside 'dfs' is 'DWARFS'.
(Other definitions for dwarfs that I've seen before include "See 6" , "Mythical short beings" , "Dominates" , "Overshadows" , "Short mythical creatures" .)