Owner-occupier's about to secure centre (4)
I believe the answer is:
core
'centre' is the definition.
(core is a kind of centre)
'owner-occupier's about to secure' is the wordplay.
'to secure' indicates the answer is hidden within the clue (I've seen 'securing' mean this).
'about' says the letters should be written in reverse.
'eroc' is hidden within 'owner occupiers'.
'eroc' reversed gives 'CORE'.
(Other definitions for core that I've seen before include "Inmost part" , "Planet's centre" , "The centre part, as of an apple" , "Drilled rock sample" , "Kernel" .)