How many letters does the top answer for “strike heavily, especially with the fist or a bat” have?

The most common answer is slog (4 letters).

Crossword clue: strike heavily, especially with the fist or a bat

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

slog 4 letters wn-def

strike heavily, especially with the fist or a bat

slug 4 letters wn-def

strike heavily, especially with the fist or a bat

strike hard, especially with the fist 50% similar → clout