A professional wrestling term for a wrestling move (wrestling maneuver), STF refers to spinning toe hold facelock.
This move is in the category of submission holds.
The first time I saw this move was by some Japanese wrestler who I can't remember.
This move is a bit hard to describe. it consists of a spinning toe hold, which uses one's legs to twist and lock the opponents legs into a painful position (the victim on his stomach, the holder standing up), and a facelock, which is yanking on a guy's face (or more like head) whilst the victim is belly down on the ground, in a kind of half camel clutch.
Not all that exciting to watch, and perhaps painful, it's a little difficult to imagine it really hurting. From most angles, it looks like two guys lying on the ground next to each other.
Lord Steven Regal (William Regal) uses a variation on the STF as a finishing move, calling it the Regal Stretch.