How many letters does the top answer for “vacuously or complacently and unconsciously foolish” have?

The most common answer is fatuously (9 letters).

Crossword clue: vacuously or complacently and unconsciously foolish

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

fatuously 9 letters wn-def

vacuously or complacently and unconsciously foolish

inanely 7 letters wn-def

vacuously or complacently and unconsciously foolish