Mischievous Austrians shun US ruler's wife (7)
I believe the answer is:
tsarina
'ruler's wife' is the definition.
(I've seen this in another clue)
'mischievous austrians shun us' is the wordplay.
'mischievous' indicates an anagram.
'shun' is a deletion indicator.
'austrians' with 'us' taken away is 'atrians'.
'atrians' anagrammed gives 'TSARINA'.
(Other definitions for tsarina that I've seen before include "queen" , "Nicholas's wife" , "titled lady" , "Wife of former Russian ruler" , "Wife of royal Russian" .)