diametrical in WordNet English dictionary

1. related to or along a diameter
   "the diametral plane"
   diametral  diametric  diametrical 
   
2. characterized by opposite extremes; completely opposed
   "in diametric contradiction to his claims"; "diametrical (or opposite) points of view"; "opposite meanings"; "extreme and indefensible polar positions"
   diametric  diametrical  opposite  polar