The most common and most likely answer to this crossword clue is the 6 letter word JERSEY
I've seen this crossword clue in Financial Times
J
E
R
S
E
Y
More clues leading to the result JERSEY
- Something one may put on an island
- Small island's football shirt
- Jumper is indeed on back to front after a whiff of joint
- Top that could be lower?
- Top location in English Channel
- Warmer island off southern England
- I agree about judge going over the top
- Producer of milk with thick top
- Fine fabric often associated with royals
- Jumper – the one that jumped over the moon maybe?
Buddy explains!

The straight part
We know that "top" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case top = jersey.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.
What does JERSEY mean?
JERSEY noun- A garment knitted from wool, worn over the upper body.
- A shirt worn by a member of an athletic team, usually oversized, typically depicting the athlete's name and team number as well as the team's logotype.
- A type of fabric knit