Bedroom's solid with the French (7)
I believe the answer is:
cubicle
'bedroom's' is the definition.
(thesaurus)
'solid with the french' is the wordplay.
'solid' becomes 'cubic' (similar in meaning).
'with' means one lot of letters go next to another.
'the french' becomes 'le' ('the' in French).
'cubic'+'le'='CUBICLE'
(Other definitions for cubicle that I've seen before include "bay" , "Partitioned-off part of room" , "Cell" , "Small area for sleeping or dressing" , "Small room for special use" .)