The most common and most likely answer to this crossword clue is the 4 letter word BALI
I've seen this crossword clue in The Daily Telegraph
B
A
L
I
More clues leading to the result BALI
- British woman abandoning son in Indonesian island
- British boxer comes to island
- British boxer comes to an island
- One little doggy running around island
- Airline left India for island
- One having party back in holiday island
- Part of Indonesia vital to global industry
- Holiday island where I party, doing a turn
- Island into cruciverbalism
- Bail out in the Indian Ocean
Buddy explains!

The straight part
We know that "tropical resort" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tropical resort = bali.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.