How many letters does the top answer for “smoothly and without difficulty; precisely and deftly” have?

The most common answer is cleanly (7 letters).

Crossword clue: smoothly and without difficulty; precisely and deftly

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

cleanly 7 letters wn-def

smoothly and without difficulty; precisely and deftly

flawlessly 10 letters wn-def

smoothly and without difficulty; precisely and deftly