Volunteer force's excessive enthusiasm for island state (8)
I believe the answer is:
tasmania
'island state' is the definition.
'Tasmania' can be an answer for 'state' (Tasmania is an example). I'm not certain of the 'island' bit.
'volunteer force's excessive enthusiasm' is the wordplay.
'volunteer force's' becomes 'ta's' (I've seen this in other clues).
'excessive enthusiasm' becomes 'mania' (I've seen this in another clue).
'tas'+'mania'='TASMANIA'
'for' is the link.
Can you help me to learn more?
(Other definitions for tasmania that I've seen before include "What a relief!" , "Antipodean island state" , "Australian island state" , "Van Diemen's Land" , "Island state off SE Australia, capital Hobart" .)