Sketchy - Featureless and therefore difficult and hard-to-protect rock.
Slack - Extra rope.
Slings - A sling of nylon or Spectra/nylon, webbing or cord. Usually carried over one's shoulder - single, doubled or tripled, depending on the length of the sling.
Sloper - A hold which is sloping, not incut.
Smearing - Technique in which the climber gains purchase on the rock using friction from the sole of the shoe.
Spanish Penguin Rest - Coined in Spain, 2013. Where the climber stands on a shallow ledge pressed against the wall, but is in a position to shake-out his/her hands by flapping them by their side.
Sport climbing - Climbing routes on which pre-placed bolts are used for protection.
Spot - To protect a climber by preparing to prevent their head from hitting the ground if they were to fall.
Static Rope - A kernmantle rope with no elasticity, e.g. a haul line.
Take - To hold the climber tightly with the rope.
Toe Hooking - The same type of manoeuvre as a heel hook, only executed with the toe.
Top rope - Any situation in which the belay is above the climber.
Traditional climbing - Climbing routes on which removable gear is placed for protection by the leader as he/she ascends. The second removes the gear.
Webbing - Flat profile nylon.
Whipper - A long lead fall in which the leader is jerked about on the end of the rope.
Wire - See nut
Y.D.S. - Yosemite Decimal System for rating climb difficulty (ranging from 5.0 to 5.14).
Z-Clip - Clipping the highest point of protection with a section of rope pulled up from below the last piece you clipped. This a dangerous practice, and should be avoided.