The most common and most likely answer to this crossword clue is the 8 letter word KINGSTON
I've seen this crossword clue in Independent
K
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More clues leading to the result KINGSTON
- Island capital, where a great weight put on college
- Man accompanies boy round the northern capital
- Family’s not circling round entrance to Greater London borough
- Capital port that could be excellent if the top 50% is saved for later?
- Fours swap places in tremendous location on the Thames
- Cards not returned to capital
- Fracking stones securing capital
- Men not raised in island capital
Buddy explains!

The straight part
We know that "capital (of Jamaica)" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case capital (of jamaica) = kingston.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.