Ryan is possibly an Arab (6)
I believe the answer is:
syrian
'an arab' is the definition.
(I've seen this in another clue)
'ryan is possibly' is the wordplay.
'possibly' indicates anagramming the letters.
'ryan'+'is'='ryanis'
'ryanis' is an anagram of 'SYRIAN'.
(Other definitions for syrian that I've seen before include "Asian" , "One from Damascus, say" , "Nationality of a citizen of Damascus" , "Damascus is this capital" , "ME national" .)