Dilapidated horse-drawn carriage carrying two bishops (6)
I believe the answer is:
shabby
'dilapidated' is the definition.
(I've seen this before)
'horse-drawn carriage carrying two bishops' is the wordplay.
'two bishops' means two substitutions for 'bishop'.
'horse-drawn carriage' becomes 'shay' (I've seen this in another clue).
'carrying' indicates putting letters inside.
'bishop' becomes 'B' (chess abbreviation).
'bishop' becomes 'B' (chess abbreviation).
'b'+'b'='bb'
'shay' enclosing 'bb' is 'SHABBY'.
(Other definitions for shabby that I've seen before include "Down-at-heel - mean" , "Dingy; dishonourable" , "Of clothes, worn and threadbare (6)" , "Threadbare - despicable" , "Seedy and rundown" .)