The most common and most likely answer to this crossword clue is the 3 letter word IVY
I've seen this crossword clue in The Times
I
V
Y
More clues leading to the result IVY
- Historian, no end of social climber
- Climber, one going over sides of valley
- Girl returning in May, victorious
- Girl, a climber
- Climber in cream, not gold
- Merchant’s partner stripping away gold wall covering
- Institute Varsity’s fell climber
- Four-year climber
- Climber number four on Yorkshire’s peak
- Starts off in Vales, Yorkshire climber
Buddy explains!

The straight part
We know that "climber" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case climber = ivy.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 IVY mean?
IVY noun- Any of several woody, climbing or trailing evergreen plants of the genus Hedera.
- Any similar plant of any genus.