| sing soprano |
| sinking ship |
| sit back |
| sit on |
| sit on one's hands |
| sit through |
| sitting pretty |
| six of one, half a dozen of the other |
| six ways to Sunday |
| skate one's lane |
| skeleton at the feast |
| ski-jump nose |
| skin trade |
| skirt chaser |
| skyrocketed |
| slap leather |
| sleep |
| sleep in |
| sleep in heavenly peace |
| sleep together |
| sleeves from one's vest |
| sling along |
| sling to |
| slip of the tongue |
| slip the cable |
| slit someone's throat |
| slow-burn |
| slow off the mark |
| slow-walk |
| small change |
| small print |
| smart as a whip |
| smash someone's face in |
| smell a rat |
| smell like a tart's handbag |
| smell one's own farts |
| smile from ear to ear |
| smoke out |
| smooth down |
| snake eyes |
| snap back |
| snap out of |
| snatch the pebble |
| sneck posset |
| snipe hunt |
| snowball effect |
| snow job |
| snuggle bunny |
| so be it |
| social lubricant |
| so far |
| soften the blow |
| soft Mick |
| soft spot |
| some old |
| someone's jaw dropped |
| something is rotten in the state of Denmark |
| somewhere over the rainbow |
| songbird |
| sore-thumbish |
| so true, bestie |
| soup-to-nuts |
| sour tooth |
| space out |
| spanner in the works |
| spare tire |
| speak for oneself |
| speak of the devil and he shall appear |
| speak to |
| spearhead |
| special relationship |
| speech is silver, silence is golden |
| sperm donor |
| spiff up |
| spill one's seed |
| spin doctor |
| spin someone's wheels |
| spit in the wind |
| spit out |
| splash down |
| split one's sides |
| split up |
| spoil someone rotten |
| spot check |
| spread one's wings |
| spring for |
| spruce up |
| square on |
| squash the beef |
| stab in the dark |
| stage business |
| staircase wit |
| stand and deliver |
| stand corrected |
| stand firm |
| stand in one's own light |
| stand on ceremony |
| stand on one's own two feet |
| stand pat |
| stand to reason |