Boy on French island gets a thrill (7)
I believe the answer is:
frisson
'a thrill' is the definition.
(synonyms)
'boy on french island' is the wordplay.
'boy' becomes 'son' (synonyms).
'on' means one lot of letters go next to another.
'french' becomes 'fr'.
'island' becomes 'is'.
'fr'+'is'='fris'
'son' put after 'fris' is 'FRISSON'.
'gets' acts as a link.
(Other definitions for frisson that I've seen before include "Shiver of excitement" , "A shudder or thrill" , "Emotional thrill" , "Strong feeling of excitement, thrill" , "Kick" .)