| slake | To satisfy (a craving or desire), quench | |
| slander | The action or crime of making a false spoken statement damaging to a person's reputation | |
| slatternly | Untidy and dirty through habitual neglect; carelessly slovenly | |
| slipshod | Characterized by a lack of care, thought, or organization | |
| slovenly | Messy or untidy in appearance or habits | |
| sojourn | A temporary stay at a place | |
| solecism | A grammatical mistake or error in language | |
| solicitous | Showing concern or care for someone's health, happiness, or welfare | |
| solidarity | Unity or agreement of feeling or action, especially among individuals with a common interest; mutual support within a group | |
| solipsistic | Relating to the philosophical theory that only the self is real and that the self cannot be aware of anything else except its own existence | |