Syrup from Caribbean island largely in East (9)
I believe the answer is:
grenadine
'syrup' is the definition.
(grenadine is a kind of syrup)
'caribbean island largely in east' is the wordplay.
'caribbean island' becomes 'grenada' (I've seen this before).
'largely' means to remove the last letter.
'east' becomes 'e' ('E' can be a synonym of 'east').
'grenada' with its final letter taken away is 'grenad'.
'grenad'+'in'+'e'='GRENADINE'
'from' is the link.
(Other definitions for grenadine that I've seen before include "Pomegranate cordial" , "material" , "Sweet cordial" , "Pomegranate juice syrup" , "West Indian" .)