The most common and most likely answer to this crossword clue is the 10 letter word LAH-DI-DAH
I've seen this crossword clue in Independent
L
A
H
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D
I
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D
A
H
More clues leading to the result LAH-DI-DAH
- Fancy if I possessed lentils from the east
- Posh boy Henry grabbed – I owned up
- Had Prince dramatically recalled accepting Princess with a superior attitude?
- Ostentatious ayatollah did a Hajj, setting off late and finishing early
- Dahl hid a wrongly written pretentious speech
- Pretentious boy got high before I had returned
- Pompous lad had his faults not having succeeded
Buddy explains!

The straight part
We know that "with a superior attitude?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case with a superior attitude? = lah-di-dah.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 LAH-DI-DAH mean?
LAH-DI-DAH adjective- Of or from the upper class of society.
- Affecting upper-class or superior airs.
- (mildly) Expression of disdain for pretension or haughtiness.
- Not a care in the world (used in a sing-song voice, for childhood rhymes)