Dilapidated building (4)
I believe the answer is:
ruin
'dilapidated building' is the definition.
(dilapidated or ruined building)
This is the entire clue.
(Other definitions for ruin that I've seen before include "State of devastation and destruction" , "Devastate" , "building now demolished" , "Scotch" , "Utter destruction or downfall" .)