Opening bars with some quaint rooms (5)
I believe the answer is:
intro
'opening bars' is the definition.
(opening bars of a piece of music)
'with some quaint rooms' is the wordplay.
'with' indicates a hidden word.
'INTRO' is hidden within 'some quaint rooms'.
(Other definitions for intro that I've seen before include "Instrumental part at start of song" , "Jazz piece" , "Nitro (anag.)" , "Launch" , "Opening bars (abbr)" .)