How many letters does the top answer for “in a terribly evil manner” have?

The most common answer is heinously (9 letters).

Crossword clue: in a terribly evil manner

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

heinously 9 letters wn-def

in a terribly evil manner

as a devil; in an evil manner 50% similar → diabolically, fiendishly

in a malign and evil manner 50% similar → malignly

in a wicked evil manner 50% similar → evilly, wickedly