How many letters does the top answer for “moving toward the south” have?

The most common answer is southbound (10 letters).

Crossword clue: moving toward the south

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

southbound 10 letters wn-def

moving toward the south

southward 9 letters wn-def

toward the south

moving toward the east 50% similar → eastbound, eastward

moving toward the north 50% similar → northbound, northward

moving toward the west 50% similar → westbound, westerly, westward