Well, we're heading into the tail end of the alphabet now, but still the Scots are chucking wonderful words in there...

skelf - Scottish a splinter or sliver of wood

skimmington - a kind of procession once undertaken to make an example of a nagging wife or an unfaithful husband (which sounds incredibly upper middle class for some reason)

skycap - a porter at an airport

snakebitten - N. Amer. informal unlucky or doomed to misfortune

snollygoster - a shrewd or unprincipled person

sockdolager - US informal a heavy blow

solander - a protective box made in the form of a book, for holding items such as botanical specimens, maps, and colour plates

soucouyant - a kind of witch, in eastern Caribbean folklore, who is believed to shed her skin by night and suck the blood of her victims (how cool is that?)

soul case - N. Amer. & W. Indian the human body

soul catcher - a hollowed bone tube used by a North American Indian medicine man to keep a sick person's soul safe while they are sick

spaghettification - the process by which, in some theories, an object would be stretched and ripped apart by gravitational forces on falling into a black hole (prior to being eaten by the spaghetti monster?)

spitchcock - an eel, split and then grilled or fried (the chicken version is a spatchcock)

splanchnic - having to do with the the viscera or internal organs, especially those of the abdomen (and sounds like what you'd do to someone to reveal those organs)

spurrier - a person who makes spurs

stercoraceous - consisting of or resembling dung or faeces (I'm sure there's a four letter word that is more succinct)

sternutator - something that causes sneezing

stiction - the frictional force which hinders an object from being moved while in contact with another (oh come on, someone made that up)

strappado - a punishment or torture in which the victim was hoisted in the air on a rope and then allowed to fall almost to the ground before being stopped with an abrupt jerk

strigil - an instrument with a curved blade used by ancient Greeks and Romans to scrape sweat and dirt from the skin in a hot-air bath or after exercise

struthious - having to do with or resembling an ostrich

studmuffin - N. Amer. humorous a sexually attractive, muscular man

stylite - a early Christian ascetic who lived standing on top of a pillar (wondering if that's where the expression to 'drop off to sleep' comes from...)

subfusc - the dark formal clothing worn for examinations and ceremonial or formal occasions at some universities (my wife had one of these, but I went to Polytechnic so we had hoodies)

submontane - passing under or through mountains, or situated on the lower slopes of a mountain range

succuss - to shake something vigorously, especially a homeopathic remedy (or something done if you get a skelf, suck your finger and curse at the same time)

sudd - an area of floating vegetation that impedes navigation in a stretch of the White Nile

suedehead - a youth like a skinhead but with slightly longer hair and smarter clothes

sun-grazing - (of a comet) having an orbit which passes close to the sun

superbious - proud and overbearing

superette - N. Amer. a small supermarket