How many letters does the top answer for “characterized by opposite extremes; completely opposed” have?

The most common answer is diametric (9 letters).

Crossword clue: characterized by opposite extremes; completely opposed

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

diametric 9 letters wn-def

characterized by opposite extremes; completely opposed

diametrical 11 letters wn-def

characterized by opposite extremes; completely opposed