Jibe about backward Nordic girl (8)
I believe the answer is:
jennifer
'girl' is the definition.
'jibe about backward nordic' is the wordplay.
'jibe' becomes 'jeer'.
'about' means one lot of letters goes inside another.
'backward' is a reversal indicator.
'nordic' becomes 'finn' (person from Finland).
'finn' in reverse letter order is 'nnif'.
'jeer' enclosing 'nnif' is 'JENNIFER'.
(Other definitions for jennifer that I've seen before include "Girl's name" , "Ms Aniston, by name" , "Girl" .)