Rewired Sion East for sound (5)
I believe the answer is:
noise
'sound' is the definition.
(noise is a kind of sound)
'rewired sion east' is the wordplay.
I cannot quite see how this works, but
an anagram of 'sion' is 'nois' which is present in the answer.
'east' could be 'e' (synonyms) and 'e' is found within the answer.
No letters remain.
This explanation may well be incorrect...
'for' is the link.
Can you help me to learn more?
(Other definitions for noise that I've seen before include "Unpleasant sounds" , "Static - sound" , "Loud or disturbing sound" , "Racket, din" , "Unwanted sounds" .)