How many letters does the top answer for “one living beyond the mountains; hence, a foreigner; a stranger.” have?

The most common answer is tramontane (10 letters).

Crossword clue: one living beyond the mountains; hence, a foreigner; a stranger.

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

tramontane 10 letters web-def

a cold dry wind that blows south out of the mountains into Italy and the western Mediterranean