The most common and most likely answer to this crossword clue is the 5 letter word NOISY
I've seen this crossword clue in Financial Times
N
O
I
S
Y
More clues leading to the result NOISY
- Raucous number’s the finale of “Company”
- Piercing? One’s unduly curious about it
- One stops interfering, becoming vociferous
- Number one — extremely sorry it’s loud
- Loud individual bitten by Snoopy
- Inquisitive about one being vociferous
- Loud part of casino is yours
- Curious about Philistine being rowdy
- Top seed, say, lacks gut for making racket
- Like some sound rising that is to be restricted
Buddy explains!

The straight part
We know that "vociferous" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vociferous = noisy.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 NOISY mean?
NOISY adjective- Making a noise, especially a loud unpleasant sound
- Full of noise.
- Unpleasant-looking and causing unwanted attention