A fee for passing island (5)
I believe the answer is:
atoll
'passing island' is the definition.
'atoll' can be an answer for 'island' (I've seen this in another clue). I'm unsure of the 'passing' bit.
'a fee' is the wordplay.
'fee' becomes 'toll' (toll is a kind of fee).
'a'+'toll'='ATOLL'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for atoll that I've seen before include "Ring-shaped coral island" , "Ring of coral" , "Allot (anag.)" , "Coral isle" , "Pacific coral island" .)