The most common and most likely answer to this crossword clue is the 6 letter word TAIWAN
I've seen this crossword clue in Independent
T
A
I
W
A
N
More clues leading to the result TAIWAN
- Island's top-class whiskey consumed in function
- I want Altair cycling country
- Await trouble on North Pacific island
- One in temple raised on an island off the Chinese mainland
- Island in East that is oddly lacking in colour
- I want a free country
- Want diverted main route to divide foreign island
- Island, one I want to travel around
- Island where Brown consumes excellent whiskey
- 11a
Buddy explains!

The straight part
We know that "Island" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case island = taiwan.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.