The most common and most likely answer to this crossword clue is the 4 letter word EXPO
I've seen this crossword clue in Financial Times
E
X
P
O
More clues leading to the result EXPO
- Bombshell removed from casing for show
- Show some of convex polyhedron
- Show wrong sign in European river
- Sexpot’s revealing show
- Next spot opened for trade fair
- Show skinned peach
- Public showing what fills faex populi
- Fair old pan having bottom scrubbed
- Attractive person shaved for public display
- Show past name for “chamber pot”
Buddy explains!

The straight part
We know that "trade fair" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case trade fair = expo.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 EXPO mean?
EXPO noun- An exposition.
- An expediter; a restaurant worker who prepares food to be taken to tables.