The most common and most likely answer to this crossword clue is the 5 letter word VOLTE
I've seen this crossword clue in The Times
V
O
L
T
E
Buddy explains!

The straight part
We know that "U-turn" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case u-turn = volte.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 VOLTE mean?
VOLTE noun- A turning; a time (chiefly used in phrases signifying that the part is to be repeated).
- A volte
- A turning point or point of change in a poem, most commonly a sonnet.