The most common and most likely answer to this crossword clue is the 7 letter word RATTLER
I've seen this crossword clue in The Times
R
A
T
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R
More clues leading to the result RATTLER
- Dog hunting vermin traps large snake
- Poisonous American incessant talker topped
- Such a telling blow? SOS could be desperate last resort
- Chatterbox, not quiet – noisy type
- Unnerve Republican who's got a nasty bite?
- Vermin-killing cat biting large snake
- Snake right under child’s toy
- Repelled at first by toy snake
- Snake of an old politician nearly getting taken in by Republicans
- In America it might kill Simon King
Buddy explains!

The straight part
We know that "noisy type" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case noisy type = rattler.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 RATTLER mean?
RATTLER noun- Anything that rattles.
- A rattlesnake.
- A freight train or, , a decrepit passenger train.
- A loud, inconsiderate talker.
- A stunning blow.
- An impudent lie; a whopper.