Mary-Anne, some Indo-European (5)
I believe the answer is:
aryan
'indo-european' is the definition.
('Aryan' can be a synonym of 'indo-european')
'mary-anne some' is the wordplay.
'some' says the answer is hidden in the clue.
'ARYAN' is hidden in the letters of 'mary anne'.
(Other definitions for aryan that I've seen before include "Ancient language" , "One of an ancient people" , "Early Indo-European language" , "Ancient Indo-European" , "Of hte Indo-European language family" .)