Empty dining area with a fireplace installed (11)
I believe the answer is:
meaningless
'empty' is the definition.
(similar in meaning)
'dining area with a fireplace installed' is the wordplay.
'dining area' becomes 'mess' (I've seen this before).
'with' means one lot of letters goes inside another.
'a' becomes 'an'.
'fireplace' becomes 'ingle' (I've seen this before).
'installed' means one lot of letters goes inside another.
'mess' enclosing 'an' is 'meanss'.
'meanss' enclosing 'ingle' is 'MEANINGLESS'.
(Other definitions for meaningless that I've seen before include "Without significance" , "Enamel signs (anag)" , "having no worthwhile quality" , "Empty" , "Men's angle is (anag) -- nonsensical" .)