Statement stupid idiot pens about nothing (10)
I believe the answer is:
deposition
'statement' is the definition.
(deposition is a kind of statement)
'stupid idiot pens about nothing' is the wordplay.
'stupid' indicates an anagram (in a stupid order).
'about' means one lot of letters goes inside another.
'nothing' becomes 'O' (O resembles 0).
'idiot'+'pens'='idiotpens'
'idiotpens' with letters rearranged gives 'depositin'.
'depositin' going around 'o' is 'DEPOSITION'.
(Other definitions for deposition that I've seen before include "Testimony" , "Evidence" .)