The most common and most likely answer to this crossword clue is the 7 letter word FLEMISH
I've seen this crossword clue in The Guardian
F
L
E
M
I
S
H
More clues leading to the result FLEMISH
Buddy explains!

The straight part
We know that "Belgian?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case belgian? = flemish.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 FLEMISH mean?
FLEMISH noun- A rope that has been coiled into a neat mat; a flemish coil.
- To coil a rope into a neat pattern on the deck of a ship.