Serviceman flogged, one hears, on a regular basis (7)
I believe the answer is:
soldier
'serviceman' is the definition.
(soldier is a kind of serviceman)
'flogged one hears on a regular basis' is the wordplay.
'flogged' becomes 'sold' (flog can mean to sell).
'one' becomes 'I' (Roman numeral).
'on a regular basis' indicates alternate letters.
The alternating letters of 'hears' are 'er'.
'sold'+'i'+'er'='SOLDIER'
(Other definitions for soldier that I've seen before include "Enlisted man or woman" , "One enlisted" , "Military man" , "mercenary?" , "Warrior" .)