Old American man (4)
I believe the answer is:
used
'old' is the definition.
(as in used or second-hand items)
'american man' is the wordplay.
'american' becomes 'US' (abbreviation for United States).
'man' becomes 'ed' (short for Edward).
'us'+'ed'='USED'
(Other definitions for used that I've seen before include "No longer new" , "Dog-eared" , "Sued, having been employed" , "like majority of cars?" , "Not fresh" .)