The most common and most likely answer to this crossword clue is the 11 letter word FULL-LENGTH
I've seen this crossword clue in Financial Times
F
U
L
L
-
L
E
N
G
T
H
More clues leading to the result FULL-LENGTH
Buddy explains!
The straight part
We know that "Achievement in pool, perhaps/touching ground?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case achievement in pool, perhaps/touching ground? = full-length.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 FULL-LENGTH mean?
FULL-LENGTH adjective- Not shortened; complete and uncut
- (of clothing) Covering the full height of the body
- (of a painting or sculpture) Representing the full height of the body
- At full stretch, requiring the whole body.