Staff officer cleared out base of operations (5)
I believe the answer is:
manor
'base of operations' is the definition.
'manor' can be an answer for 'base' (I have seen 'Operational base' mean 'manor' so perhaps 'base' could also mean 'manor'). I am not sure about the 'of operations' bit.
'staff officer cleared' is the wordplay.
'staff' becomes 'man' (as in staffing or manning a particular place).
'cleared' suggests removing the centre (the inside letters are cleared out).
'officer' with its middle taken out is 'or'.
'man'+'or'='MANOR'
'out' is the link.
Can you help me to learn more?
(Other definitions for manor that I've seen before include "Landed estate" , "Nobleman's land" , "police area" , "Lord's estate" , "patch" .)