Part of Jamaica, principally a holiday resort (5)
I believe the answer is:
capri
'resort' is the definition.
(Italian resort island)
'part of jamaica principally a holiday' is the wordplay.
'part of' indicates the answer is hidden within the clue.
'CAPRI' is hidden within 'jamaica principally holiday'.
(Other definitions for capri that I've seen before include "popular resort" , "I carp about the island" , "Romantic Isle in Bay of Naples" , "Island near Naples" , "Italian resort island, once home to Gracie Fields" .)