Marianne's new nationality (8)
I believe the answer is:
armenian
'nationality' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'marianne's new' is the wordplay.
'new' indicates an anagram.
'marianne' anagrammed gives 'ARMENIAN'.
Can you help me to learn more?
(Other definitions for armenian that I've seen before include "language" , "ethnic group in Asia" , "Person from Yerevan, say" , "of the Southern Caucasus" , "Eg, native of Yerevan" .)