How many letters does the top answer for “(of a body of water) free from disturbance by heavy waves” have?

The most common answer is placid (6 letters).

Crossword clue: (of a body of water) free from disturbance by heavy waves

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

placid 6 letters wn-def

(of a body of water) free from disturbance by heavy waves

tranquil 8 letters wn-def

(of a body of water) free from disturbance by heavy waves

unruffled 9 letters wn-def

(of a body of water) free from disturbance by heavy waves