Sibilances refer to a hissing or whispering sound in speech, often produced by the fricative consonants like 's' or 'sh'. There are several synonyms for this word that are equally useful. One of the most common alternatives is 'hiss', which describes the same sound quality as sibilances. 'Whisper' is another apt synonym since both words imply a soft, quiet sound. 'Susurration' is a less frequently used word that refers specifically to a soft murmuring, rustling sound. 'Murmur' and 'whispering' are two other synonyms that work well to describe sibilances. Overall, these synonyms help to expand the lexicon and add variety to our vocabulary.