The most common and most likely answer to this crossword clue is the 5 letter word BULGE
I've seen this crossword clue in Financial Times
B
U
L
G
E
More clues leading to the result BULGE
- Bulk large on the outside?
- Listening device left in – note something sticking out
- Learner advances in brass instrument – that’s swell
- Part of leg lubricated when reviewing swelling
- I’m involved with this battle site in Belgium
- Swelling from insect biting lady on top eyelid initially
- Replacing this compiler with uniform rubbish would be swell
- Protrusion in horn after some internal adjustment
- Stick out a blown bugle
Buddy explains!

The straight part
We know that "battle site in Belgium" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case battle site in belgium = bulge.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 BULGE mean?
BULGE noun- Something sticking out from a surface; a swelling, protuberant part; a bending outward, especially when caused by pressure.
- The bilge or protuberant part of a cask.
- The bilge of a vessel.
- The outline of male genitals visible through clothing.
- A sudden rise in value or quantity.
- To stick out from (a surface).
- To bilge, as a ship; to founder.