The most common and most likely answer to this crossword clue is the 7 letter word IRONMAN
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The straight part
We know that "race" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case race = ironman.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 IRONMAN mean?
IRONMAN noun- An extremely tough and strong athlete, especially one who competes in extreme athletic competitions or in a large number of games consecutively.
- A form of surf lifesaving competition which combines swimming, board paddling, ski paddling and running.
- An extreme form of triathlon, expecially one organised by the World Triathlon Corporation that comprises a 2.4 mile swim, a 112 mile bike race and a marathon run.
- (by extension) The winner of such a lifesaving event or triathlon.