How many letters does the top answer for “lacking conviction or boldness or courage” have?

The most common answer is faint (5 letters).

Crossword clue: lacking conviction or boldness or courage

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

faint 5 letters wn-def

pass out from weakness, physical or emotional distress due to a loss of blood supply to the brain

fainthearted 12 letters wn-def

lacking conviction or boldness or courage

the trait of lacking boldness and courage 60% similar → faintheartedness