Old historian abandoning States -- understood? (5)
I believe the answer is:
tacit
'understood?' is the definition.
(I've seen this before)
'old historian abandoning states' is the wordplay.
'old historian' becomes 'tacitus' (I've seen this before).
'abandoning' suggests deleting specific letters.
'states' becomes 'US' (abbreviation for the United States).
'tacitus' with 'us' taken out is 'TACIT'.
(Other definitions for tacit that I've seen before include "Understood, not spoken or played" , "Implicitly understood" , "Implied without being said" , "Understood without being directly expressed" , "Implied, not spoken" .)