Arab possibly wasted US aid (5)
I believe the answer is:
saudi
'arab' is the definition.
(Saudi is an example)
'wasted us aid' is the wordplay.
'wasted' indicates an anagram.
'us'+'aid'='usaid'
'usaid' anagrammed gives 'SAUDI'.
'possibly' acts as a link.
(Other definitions for saudi that I've seen before include "Not hard" , "Native of kingdom" , "One from Riyadh" , "Middle-Easterner" , "Native of Riyadh, possibly" .)