Judge on island is up in arms (5)
I believe the answer is:
irate
'up in arms' is the definition.
(I've seen this in another clue)
'judge on island' is the wordplay.
'judge' becomes 'rate' (rating is a kind of judging).
'on' says to put letters next to each other.
'island' becomes 'i' (geographical abbreviation).
'rate' put after 'i' is 'IRATE'.
'is' acts as a link.
(Other definitions for irate that I've seen before include "Fuming" , "Ticked off" , "Wrathful" , "Extremely angry" , "will be up in arms" .)