The most common and most likely answer to this crossword clue is the 5 plus 4 letter word MARCO POLO
I've seen this crossword clue in The Times
M
A
R
C
O
P
O
L
O
More clues leading to the result MARCO POLO
- Traveller upset when given small company car
- Traveller given brandy and old game
- Old European explorer hurt fellow on equestrian pursuit
- Bucks town mostly welcoming busy old traveller
- Traveller‘s hurt before county game
- Traveller wants nothing sweet after a brandy
- Nothing between brandy and candy for travel writer
- Travelling merchant hurt company with game
- Noted explorer making name once in US politics and sport
- Explorer or a cool MP, perhaps
Buddy explains!

The straight part
We know that "Traveller" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case traveller = marco polo.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.