How many letters does the top answer for “a worker who drives mules” have?

The most common answer is muleteer (8 letters).

Crossword clue: a worker who drives mules

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

muleteer 8 letters wn-def

a worker who drives mules

skinner 7 letters wn-def

a worker who drives mules

one who drives mules. 50% similar → muleteer