Playing about with old Peruvian (4)
I believe the answer is:
inca
'old peruvian' is the definition.
(the Inca were a historical people of Peru)
'playing about' is the wordplay.
'playing' becomes 'in'.
'about' becomes 'ca' (abbreviation for circa).
'in'+'ca'='INCA'
'with' is the link.
(Other definitions for inca that I've seen before include "Pre-conquest Andean" , "Former emperor" , "Early Peruvian" , "Native Peruvian" , "Member of old South American Indian people of Peru" .)