One going one on one in an ancient region (5)
I believe the answer is:
ionia
'an ancient region' is the definition.
'Ionia' can be an answer for 'region' (Ionia is an example). I am unsure of the 'an ancient' bit.
'one going one on one' is the wordplay.
'one' becomes 'i' (Roman numeral).
'going' becomes 'on' (both can mean functioning or activated).
'one' becomes 'i' (Roman numeral).
'on' says to put letters next to each other.
'one' becomes 'a' (a thing is one thing).
'i'+'on'+'i'+'a'='IONIA'
'in' is the link.
Can you help me to learn more?
(Other definitions for ionia that I've seen before include "Old region in Asia Minor" , "Aegean region which gives its name to the adjacent sea" , "where Greeks settled" , "Classical Aegean region" , "Old territory" .)