Quick to knock with papers (5)
I believe the answer is:
rapid
'quick' is the definition.
(synonyms)
'knock with papers' is the wordplay.
'knock' becomes 'rap' (synonyms).
'with' says to put letters next to each other.
'papers' becomes 'ID' (identifying documents are one's 'papers').
'rap'+'id'='RAPID'
'to' is the link.
(Other definitions for rapid that I've seen before include "Fast, quick" , "Fast, speedy" , "Flying" , "Electrical connector" , "haste" .)