The most common and most likely answer to this crossword clue is the 10 letter word PENTATHLON
I've seen this crossword clue in Financial Times
P
E
N
T
A
T
H
L
O
N
More clues leading to the result PENTATHLON
- Introducing hard line, write rubbish about athletic contest
- On tenth lap, running in athletics event
- Writer, 50, on about that cracking athletics competition
- Running on tenth lap in old Olympic event
- Collapsed on tenth lap in Olympic event
- Write that silly line about Olympic event
- The plant grows wild on part of track and field
- Blight on the plant? This needs fencing
- Collapsed on tenth lap in this challenge
Buddy explains!

The straight part
We know that "athletics competition" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case athletics competition = pentathlon.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 PENTATHLON mean?
PENTATHLON noun- An ancient athletics discipline, featuring five events: stadion, wrestling, long jump, javelin and discus
- Modern pentathlon.