How many letters does the top answer for “to prove or to refute by proof; to clear (one's self).” have?

The most common answer is deraign (7 letters).

Crossword clue: to prove or to refute by proof; to clear (one's self).

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

deraign 7 letters web-def

To prove or to refute by proof; to clear (one's self). [Obs.]

derain 6 letters web-def

To prove or to refute by proof; to clear (one's self). [Obs.]