Roman general an old man seizing control (7)
I believe the answer is:
agrippa
'roman general' is the definition.
(Marcus Vipsanius Agrippa, Roman general)
'an old man seizing control' is the wordplay.
'an' becomes 'a'.
'old man' becomes 'pa' (both can mean someone's father).
'seizing' indicates putting letters inside (inserted letters are seized).
'control' becomes 'grip' (grip is a kind of control).
'a'+'pa'='apa'
'apa' placed around 'grip' is 'AGRIPPA'.
(Other definitions for agrippa that I've seen before include "one of the Herods" , "Old general" , "10 [GENERAL]" , "Roman leader" , "General who beat Mark Antony at Actium" .)