Frenzied female relative knocked over European (6)
I believe the answer is:
maenad
'frenzied female' is the definition.
(I've seen this before)
'relative knocked over european' is the wordplay.
'relative' becomes 'ma' (ma is a kind of relative).
'knocked over' says the letters should be written backwards.
'european' becomes 'dane' (someone from Denmark).
'dane' back-to-front is 'enad'.
'ma'+'enad'='MAENAD'
(Other definitions for maenad that I've seen before include "Wild female follower of Dionysus" , "Name da for a fierce woman" , "Female fan of Bacchus" , "Frenzied or distraught woman" , "Female votary of Dionysus or a wild woman" .)