How many letters does the top answer for “author of one flew over the cuckoo's nest” have?

The most common answer is kesey (5 letters).

Crossword clue: author of one flew over the cuckoo's nest

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

kesey 5 letters wd-fact-v3

director of one flew over the cuckoo's nest 67% similar → forman

wrote one flew over the cuckoo's nest 67% similar → kesey