The most common and most likely answer to this crossword clue is the 7 letter word MOUNTED
I've seen this crossword clue in The Daily Telegraph
M
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More clues leading to the result MOUNTED
Buddy explains!

The straight part
We know that "Climbed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case climbed = mounted.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 MOUNTED mean?
MOUNTED verb- To get upon; to ascend; to climb.
- To place oneself on (a horse, a bicycle, etc.); to bestride.
- To cause to mount; to put on horseback; to furnish with animals for riding.
- To cause (something) to rise or ascend; to drive up; to raise; to elevate; to lift up.
- To rise on high; to go up; to be upraised or uplifted; to tower aloft; to ascend; often with up.
- To attach (an object) to a support, backing, framework etc.
- To attach (a drive or device) to the file system in order to make it available to the operating system.
- (sometimes with up) To increase in quantity or intensity.
- To attain in value; to amount (to).
- To get on top of (an animal) to mate.
- To have sexual intercourse with someone.
- To begin (a campaign, military assault, etc.); to launch.
- To deploy (cannon) for use.
- To prepare and arrange the scenery, furniture, etc. for use in (a play or production).
- To incorporate fat, especially butter, into (a dish, especially a sauce to finish it).
- On horseback
- Raised on steps, generally three, as a cross
- Furnished; supplied