Fuss at home about judge becoming neighbour (6)
I believe the answer is:
adjoin
'neighbour' is the definition.
(I've seen this before)
'fuss at home about judge' is the wordplay.
'fuss' becomes 'ado' ('ado' can be a synonym of 'fuss'**).
'at home' becomes 'in' ('in' can be similar in meaning to 'at home').
'about' means one lot of letters goes inside another.
'judge' becomes 'j'.
'ado'+'in'='adoin'
'adoin' enclosing 'j' is 'ADJOIN'.
'becoming' is the link.
(Other definitions for adjoin that I've seen before include "Be next or nearest to" , "Abut, border" , "Be next to (something)" , "Be next to, like building" , "Butt up against" .)