Spending a billion, bribe aristo (5)
I believe the answer is:
noble
'aristo' is the definition.
(an aristocrat)
'spending a billion bribe' is the wordplay.
'spending' is a deletion indicator (to spend can mean to give out or give away).
'a billion' becomes 'b'.
'bribe' becomes 'nobble' (nobble can mean to bribe or attempt to influence).
'nobble' with 'b' taken away is 'NOBLE'.
(Other definitions for noble that I've seen before include "Dignified" , "gold coin, now obsolete" , "titled person" , "Lord" , "Worthy" .)