Authorise payment it legally covers in part (7)
I believe the answer is:
entitle
'authorise' is the definition.
(I know that entitle is a kind of authorise)
'payment it legally covers in part' is the wordplay.
'in part' says the answer is hidden in the clue.
'ENTITLE' can be found hidden inside 'payment it legally covers'.
(Other definitions for entitle that I've seen before include "Style; give right to" , "Name; enable" , "Give (someone) rights" , "Licence" , "Give a right (to someone to do something)" .)