The most common and most likely answer to this crossword clue is the 9 letter word FLATULENT
I've seen this crossword clue in The Times
F
L
A
T
U
L
E
N
T
More clues leading to the result FLATULENT
- Apartment unit loaned out with gas problems
- Short of air, uranium fast producing gas
- Likely to let one go fast after puncture on bend
- Pretentious uniform United hire out around November
- You say the apartment you let someone use is having a problem with gas?
- Apartment you furnished is pretentious
- Windy apartment gets upper-class lease housing central banks
- High-rise domicile you permitted use of is windy
Buddy explains!

The straight part
We know that "Pretentious" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case pretentious = flatulent.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 FLATULENT mean?
FLATULENT adjective- Affected by gas in the intestine; likely to fart.
- Empty; vain.