Break in coral mass round large island (6)
I believe the answer is:
relief
'break' is the definition.
(I know that relief is a type of break)
'coral mass round large island' is the wordplay.
'coral mass' becomes 'reef' (I've seen this in another clue).
'round' is an insertion indicator.
'large' becomes 'L' (eg in clothes sizes).
'island' becomes 'i'.
'l'+'i'='li'
'reef' enclosing 'li' is 'RELIEF'.
'in' is the link.
(Other definitions for relief that I've seen before include "Pleasure at removal of anxiety" , "Alleviation of pain or distress" , "welfare" , "Person taking over another's turn of duty" , "Alleviation; (financial) assistance" .)