To stop short or refuse to proceed

• To hesitate or resist strongly, often with balk at

To thwart, hinder, or frustrate plans or progress

Baseball: an illegal deceptive motion by the pitcher

• Runners advance one base

Billiards or snooker: the area behind the baulk line

• The starting zone for the cue ball

A beam or crossbeam; squared timber

An unploughed ridge in a field

• An earth bank at an excavation edge