How many letters does the top answer for “in an effective manner” have?

The most common answer is effectively (11 letters).

Crossword clue: in an effective manner

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

effectively 11 letters wn-def

in an effective manner

efficaciously 13 letters wn-def

in an effective manner

in a vigorous and effective manner 67% similar → trenchantly