One pushing paper to insert a cryptic? (9)
I believe the answer is:
stationer
'one pushing paper' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'to insert a cryptic?' is the wordplay.
'cryptic?' is an anagram indicator (I've seen 'cryptic' mean this (a cryptic or obscure order of the letters)).
'to'+'insert'+'a'='toinserta'
'toinserta' with letters rearranged gives 'STATIONER'.
Can you help me to learn more?
(Other definitions for stationer that I've seen before include "Seller of writing materials" , "Seller of paper, pens, etc" , "One assigning position" , "source of writing materials" , "Shopkeeper" .)