Again start getting back half rules (7)
I believe the answer is:
regimes
'rules' is the definition.
(I've seen this before)
'again start getting back half' is the wordplay.
'again' becomes 're' (prefix meaning 'again').
'start' suggests taking the first letters.
'back' says the letters should be written in reverse.
'half' becomes 'semi' (I've seen this before).
The initial letter of 'getting' is 'g'.
'semi' in reverse letter order is 'imes'.
're'+'g'+'imes'='REGIMES'
(Other definitions for regimes that I've seen before include "rules" , "Governments in power" , "Systems of government or courses of treatment" .)