The most common and most likely answer to this crossword clue is the 9 letter word FLAGELLUM
I've seen this crossword clue in The Guardian
F
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More clues leading to the result FLAGELLUM
Buddy explains!

The straight part
We know that "it provides locomotion/it provides locomotion" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it provides locomotion/it provides locomotion = flagellum.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 FLAGELLUM mean?
FLAGELLUM noun- In protists, a long, whiplike membrane-enclosed organelle used for locomotion or feeding.
- In bacteria, a long, whiplike proteinaceous appendage, used for locomotion.
- A whip