Army engineer's forged papers (6)
I believe the answer is:
sapper
'army engineer's' is the definition.
(soldier in the Corps of Royal Engineers)
'forged papers' is the wordplay.
'forged' indicates anagramming the letters.
'papers' anagrammed gives 'SAPPER'.
(Other definitions for sapper that I've seen before include "Writer" , "Royal Engineer" , "Military engineer" , "Army engineer" , "Military miner" .)