Complete wreck (5)
I believe the answer is:
total
I believe this clue is a double definition.
'complete' is the first definition.
(similar in meaning)
'wreck' is the second definition.
(to total a vehicle is to damage it beyond repair)
(Other definitions for total that I've seen before include "It might be grand" , "Count" , "Complete, entire amount" , "Everything added together" , "Unqualified" .)