It enters stormy Thai island (6)
I believe the answer is:
tahiti
'island' is the definition.
(I know that Tahiti is a island)
'it enters stormy thai' is the wordplay.
'enters' means one lot of letters goes inside another.
'stormy' indicates anagramming the letters.
'thai' anagrammed gives 'tahi'.
'it' going into 'tahi' is 'TAHITI'.
(Other definitions for tahiti that I've seen before include "Pacific island associated with Gauguin" , "Romantic Polynesian island, capital Papeete" , "I hit at this exotic island" , "South Pacific island, linked to Paul Gauguin and Robert Louis Stevenson" , "Island in South Pacific, chief town Papeete" .)