The most common and most likely answer to this crossword clue is the 3 plus 2 plus 3 letter word TUG OF WAR
I've seen this crossword clue in The Times
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More clues leading to the result TUG OF WAR
Buddy explains!
The straight part
We know that "Its winner most strongly backed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case its winner most strongly backed = tug of war.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 TUG OF WAR mean?
TUG OF WAR noun- A game or competition in which two teams pull or tug on opposite ends of a rope trying to force the other team over the line which initially marked the middle between the two teams.
- A dispute between two parties, particularly an entrenched, back-and-forth dispute.