The most common and most likely answer to this crossword clue is the 4 letter word MESA
I've seen this crossword clue in The Guardian
M
E
S
A
More clues leading to the result MESA
- Eminence of name-dropping intellectuals
- Geographical feature unchanged with halves switched
- A lot of confusion over a weathered landscape feature
- The rise of James Anderson
- Geographical feature that’s identical with top and bottom halves switched
- Occasionally meet star climbing this?
- This author at South American plateau
Buddy explains!

The straight part
We know that "climbing /this?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case climbing /this? = mesa.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 MESA mean?
MESA noun- Flat area of land or plateau higher than other land, with one or more clifflike edges.