Opposite of radial
I believe the answer is:
ulnar
'opposite of radial' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ulnar that I've seen before include "Relating to a bone in the forearm" , "Relating to a particular arm bone" , "Relating to one of the bones of the forearm" , "of certain bones" .)