Fricatives are consonant sounds that are produced by forcing air through a narrow opening in the vocal tract, resulting in a hissing or buzzing sound. There are many synonyms for the term 'fricative', which are often used interchangeably in linguistic contexts. Some common alternatives include 'sibilant' - which specifically refers to fricatives that produce a hissing or whistling sound, 'strident' - which has a stronger emphasis on the harshness of the sound, and 'spirant' - which is a broader term that refers to any sound produced by forcing air through a narrow passage in the vocal tract, whether or not it is a fricative. Other options include 'hissing', 'buzzing', or 'whistling' sounds, which are all closely related to fricatives.