European contradicting principle (4)
I believe the answer is:
pole
This clue is a double definition.
'european' is the first definition.
(Pole is an example)
'contradicting principle' is the second definition.
(as in opposite poles of a spectrum)
(Other definitions for pole that I've seen before include "Heavenly body indicating north" , "Punt propeller" , "Chopin, for example" , "Magnet end" , "Rod, perch" .)