A bit of a quiet item (8)
I believe the answer is:
particle
'a bit' is the definition.
(I have seen 'Small bit ' mean 'particle' so perhaps 'bit' could also mean 'particle')
'a quiet item' is the wordplay.
I cannot really understand how this works, but
'quiet' could be 'p' (music symbol for 'piano', ie soft or quiet) and 'p' is found in the answer.
'item' could be 'article' (I've seen this before) and 'article' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'of' is the link.
Can you help me to learn more?
(Other definitions for particle that I've seen before include "Tiny piece of matter" , "Crumb" , "Scrap" , "Small unit of matter" , "Minute piece of matter" .)