(verb) - The past participle of the Italian "to counterpose", contrapposto is also an art term which describes one particular pose an artist may give a sculpted or painted human figure. Specifically, the subject is depicted with his or her weight shifted to one leg, causing that leg to appear rigid with its knee locked, its foot flat on the ground and its hip thrust out a bit.
To visualize a real life example of the contrapposto "pose," imagine a mother holding a 9-month old baby on her hip. Serious weight bearing is going on there, and that hip is necessarily thrust out in order to keep the babe from sliding to the floor.
For you Art History purists, one of the original and best examples of contrapposto can be seen in (this copy of) the 5th century B.C. Greek sculptor Polykleitos' Doryphoros.