| Word | Definitions | Synonyms |
|---|---|---|
| fricative | (adjective) of speech sounds produced by forcing air through a constricted passage (as `f', `s', `z', or `th' in both `thin' and `then') | Synonyms: continuant, sibilant, spirant, strident |
| frictional | (adjective) pertaining to or worked or produced by friction | - |
| frictionless | (adjective) lacking all friction | - |