The most common and most likely answer to this crossword clue is the 9 letter word RUNNER-UP
I've seen this crossword clue in The Times
R
U
N
N
E
R
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U
P
More clues leading to the result RUNNER-UP
Buddy explains!
The straight part
We know that "One climbing quickly/not the winner" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one climbing quickly/not the winner = runner-up.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 RUNNER-UP mean?
RUNNER-UP noun- The person who finishes second, or in any position after the first.
- Second favorite.