How many letters does the top answer for “one who asks questions; a questioner.” have?

The most common answer is interrogator (12 letters).

Crossword clue: one who asks questions; a questioner.

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

interrogator 12 letters web-def

a questioner who is excessively harsh

one who inquires, or asks questions. swift. 50% similar → querist