How many letters does the top answer for “an angry vicious expression” have?

The most common answer is snarl (5 letters).

Crossword clue: an angry vicious expression

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

snarl 5 letters wn-def

utter in an angry, sharp, or abrupt tone