Awful jerk's penning paper (6)
I believe the answer is:
tragic
'awful' is the definition.
(I've seen this before)
'jerk's penning paper' is the wordplay.
'jerk' becomes 'tic' (jerking movement by the body).
'penning' is an insertion indicator.
'paper' becomes 'rag' (rag can mean a newspaper).
'tic' enclosing 'rag' is 'TRAGIC'.
(Other definitions for tragic that I've seen before include "Dreadful" , "Terrible" , "Shocking" , "'Very, very sad (6)'" , "Calamitous, causing great sadness" .)