Noisy old wreck going round the bend (4)
I believe the answer is:
loud
'noisy' is the definition.
(associated in meaning)
'old wreck going round the bend' is the wordplay.
'wreck' indicates anagramming the letters.
'going round' indicates putting letters inside (some letters go around others).
'the bend' becomes 'U' (a U-bend is a kind of bend - pipe under sink).
'old' with letters rearranged gives 'lod'.
'lod' enclosing 'u' is 'LOUD'.
(Other definitions for loud that I've seen before include "booming" , "Blaring" , "This speaker is" , "Deafening" , "Resounding" .)