A crack climb that is too wide for good hand and foot jams, yet too narrow to fit a climber's whole body. Uniformly cursed and avoided by the vast majority of the climbing public, offwidths hold a certain appeal for a select group of masochists (who may or may not be a sandwich or two shy of a picnic).
The most awkward width of crack: too wide for fist jamming, but too narrow to chimney. Exotic techniques for climbing them include hand stacks, heel-toe locks, knee bars, "chicken wings", and "Leavittation", but most climbers prefer to grunt, swear and thrash around, which we are reliably informed does no good at all.