The word "sibilate" means to make a hissing or whistling sound. Its antonyms would be words that represent sounds that are different from hissing or whistling. Examples of antonyms for "sibilate" would be "rumble," "roar," "boom," "clap," and "chirp." These words represent a wide range of sounds that are not associated with the hissing or whistling sound of "sibilate." By using these antonyms in writing, you can create a vivid description of a scene or event, emphasizing the variety of sounds that can be heard.