… with this malfunctioning? (5)
I believe the answer is:
organ
'with this malfunctioning?' is the definition.
The definition suggests a singular noun which matches the answer.
This is all the clue.
(Other definitions for organ that I've seen before include "with a lofty tone?" , "specialist magazine" , "Church instrument - heart, perhaps" , "Wind instrument found in the body." , "Part with special function" .)