Island has job getting rid of king — madness ensues (8)
I believe the answer is:
tasmania
'island' is the definition.
(I know that Tasmania is a island)
'job getting rid of king madness ensues' is the wordplay.
'job' becomes 'task' (synonyms).
'getting rid of' suggests deleting specific letters.
'king' becomes 'K' (abbreviation for king in chess).
'madness' becomes 'mania' (I've seen this before).
'ensues' means one lot of letters go next to another (ensue can mean to follow).
'task' with 'k' taken away is 'tas'.
'tas'+'mania'='TASMANIA'
'has' acts as a link.
(Other definitions for tasmania that I've seen before include "Australian island to south of Bass Strait" , "Antipodean island state" , "mountainous island" , "Aussie's state" , "Asian ATM in Australian federation" .)