How many letters does the top answer for “keenness and forcefulness of thought or expression or intellect” have?

The most common answer is incisiveness (12 letters).

Crossword clue: keenness and forcefulness of thought or expression or intellect

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

incisiveness 12 letters wn-def

keenness and forcefulness of thought or expression or intellect

trenchancy 10 letters wn-def

keenness and forcefulness of thought or expression or intellect