| Term | Definition |
| sequester | V. isolate; retire from public life; segregate; seclude. |
| sere | ADJ. parched; dry. |
| serendipity | N. gift for finding valuable or desirable things by accident; accidental good fortune or luck. |
| serenity | N. calmness, placidity. |
| serpentine | ADJ. winding; twisting. |
| serrated | ADJ. having a sawtoothed edge. |
| servile | ADJ. slavish; cringing. |
| servitude | N. slavery; compulsory labor; |
| sever | V. cut; separate. |
| severity | N. harshness; intensity; sternness; austerity. |
| sextant | N. navigation tool used to determine a ship's latitude and longitude. |
| shackle | V. chain; fetter. |
| sham | V. pretend. |
| shambles | N. wreck; mess. |
| shard | N. fragment, generally of pottery. |
| shaving | N. very thin piece, usually of wood. |
| sheaf | N. bundle of stalks of grain; any bundles of things tied together. |
| sheathe | V. place into a case |
| sherbet | N. flavored dessert ice. |
| shimmer | V. glimmer intermittently. |
| shirk | V. avoid (responsibility, work, etc); malinger. |
| shoddy | ADJ. sham; not genuine; inferior. |
| shrew | N. scolding woman. |
| shrewd | ADJ clever; astute. |
| shun | V. keep away from. |
| shunt | V. turn aside; divert; sidetrack. |
| shyster | N. lawyer using questionable methods. |
| sibling | N. brother or sister. |
| sibylline | ADJ. prophetic; oracular. |
| sidereal | ADJ. relating to the stars. |
| silt | N. sediment deposited by running water. |
| simian | ADJ. monkeylike. |
| simile | N. comparison of one thing with another, using the word 'like' or 'as'. |
| simper | V. smirk; smile affectedly. |
| simplistic | ADJ. oversimplified. |
| simulate | V. feign. |
| sinecure | N. well-paid position with little responsibility. |
| sinewy | ADJ. tough; strong and firm. |
| singular | ADJ. unique; extraordinary; odd. |
| sinister | ADJ. evil. |
| sinuous | ADJ. winding; bending in and out; not morally honest. |
| skeptic | ADJ. doubter; person who suspends judgment until having examined the evidence supporting a point of view. |
| skiff | N. small, light sailboat or rowboat. |
| skimp | V. provide scantily; live very economically. |
| skinflint | N. stingy person; miser. |
| skirmish | N. minor flight. |
| skittish | ADJ. lively; frisky. |
| skulduggery | N. dishonest behavior. |
| skulk | V. move furtively and secretly. |
| slacken | V. slow up; loosen. |
| slag | N. residue from smelting metal; dross; waste matter. |
| slake | V. quench; sate. |
| slander | N. defamation; utterance of false and malicious statements. |
| slapdash | ADJ. haphazard; careless; sloppy. |
| sleazy | ADJ. flimsy; unsubstantial. |
| sleeper | N. something originally of little value or importance that in time becomes very valuable. |
| sleight | N. dexterity. |
| slew | N. large quantity of number. |
| slight | N. insult to one's dignity; snub. |
| slipshod | ADJ. untidy or slovenly; shabby. |
| slither | V. slip or slide. |
| sloth | N. slow-moving tree-dwelling mammal. |
| slothful | ADJ. lazy. |
| slough | V. cast off. |
| slovenly | ADJ. untidy; careless in work habits. |
| sluggard | N. lazy person. |
| sluggish | ADJ. slow; lazy; lethargic. |
| sluice | N. artificial channel for directing or controlling the flow of water. |
| slur | N. insult to one's character and reputation; slander. |
| slur | V. speak indistinctly; mumble. |
| smattering | N. slight knowledge. |
| smelt | V. melt or blend ores, changing their chemical or composition. |
| smirk | N. conceited smile. |
| smolder | V. burn without flame; be liable to breakout at any moment. |
| snicker | N. half-stifled laugh. |
| snivel | V. run at the nose; snuffle; whine. |
| sobriety | N. moderation (especially regarding indulgence in alcohol); seriousness. |
| sodden | ADJ. soaked; dull. |
| sojourn | N. temporary-stay. |
| solace | ADJ. comfort in trouble. |
| solder | V. repair or make whole by using a metal alloy. |
| solecism | N. construction that is flagrantly incorrect grammatically. |
| solemnity | N. seriousness; gravity; |
| solicit | V. request earnestly; seek. |
| solicitous | ADJ. worried; concerned. |
| soliloquy | N. talking to oneself. |
| solitude | N. state of being alone; seclusion. |
| solstice | N. point at which the sun is farthest from the equator. |
| soluble | ADJ. able to be dissolved; able to be worked out. |
| solvent | ADJ. able to pay all debts. |
| solvent | N. substance that dissolves another. |
| somatic | ADJ. pertaining to the body; physical. |