to bend the knees and sink the body downward: to kneel, crouch, or collapse.
At its root this word describes one plain physical motion: the knees give way and the body drops toward the ground. Everything the word means grows out of that single picture. The reason it covers such a wide range is that a person, an animal, or a defeated army can all end up with their knees folded under them, but for very different reasons.
Sometimes the sinking is chosen and reverent. A worshiper kneels before God, or a subject drops to his knees before a king. Other times it is the easy repose of a strong animal, a lion settling down after a kill. And often it is the opposite of strength: a wounded man buckling, a woman overcome in childbirth, an exhausted body that simply cannot stay upright.
Because the picture is so vivid, the Bible loves to play the meanings against each other. The same motion that shows honor when a believer kneels shows helplessness when an enemy is brought down, and shows doom when idols are hauled off bowing on the backs of pack animals. When the action is forced on someone by another, the word turns causative: to bring an enemy low, to make him buckle underneath you in defeat.