Pet with a top stylist in vault (8)
I believe the answer is:
catacomb
'vault' is the definition.
(I have seen 'underground vault' mean 'catacomb' so perhaps 'vault' could also mean 'catacomb')
'pet with a top stylist' is the wordplay.
'pet' becomes 'cat' (cats are often kept as pets).
'with' says to put letters next to each other.
'top stylist' becomes 'comb' (I can't explain this - if you can you should give a lot more credence to this answer).
'cat'+'a'+'comb'='CATACOMB'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for catacomb that I've seen before include "Burial-place" , "Subterranean burial place" , "series of tunnels" , "Place to bury" , "Underground network" .)