diametrically

from WordNet (r) 3.0 (2006)

diametrically
    adv 1: as from opposite ends of a diameter; "when two honest
           witnesses give accounts of the same event that differ
           diametrically, how can anyone prove that the evidence you
           gave was deliberately false?"; "three of these brushes
           were approximately 120 feet apart and the fourth
           diametrically opposite to one of the three"

from The Collaborative International Dictionary of English v.0.48

Diametrically \Di*am"e*tric*al*ly\, adv.
   In a diametrical manner; directly; as, diametrically
   opposite.
   [1913 Webster]

         Whose principles were diametrically opposed to his.
                                                  --Macaulay.
   [1913 Webster]