The most common and most likely answer to this crossword clue is the 10 letter word NONCHALANT
I've seen this crossword clue in Financial Times
N
O
N
C
H
A
L
A
N
T
More clues leading to the result NONCHALANT
- Halt cannon shot, showing composure
- No time to absorb new chapter bloke composed
- Uncaring prince engaged in pious platitudes after French denial
- Cool number, new song about the French female
- Drama ending in afternoon tea left worker perhaps unconcerned
- Cool cat on an NHL shot
- Casual discussion about local area network underpins denial from France
Buddy explains!

The straight part
We know that "Uncaring" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case uncaring = nonchalant.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 NONCHALANT mean?
NONCHALANT adjective- Casually calm and relaxed.
- Indifferent; unconcerned; behaving as if detached.