to sink down low: to bow, stoop, crouch, or be brought low, whether a body, a spirit, or a standing structure collapsing toward the ground
This is one verb for every kind of downward collapse. A lion settles low in its den, a mourner stoops over a grave, a worn-down spirit folds in on itself, a proud wall topples into the dust: the Bible uses the same word for all of it. The core picture is not a chosen gesture but a sinking, a going-down.
Hebrew does not split the body from the inner life, so this verb slides easily from posture to state of soul. The bent back is not merely a sign of grief; it is the grief. When the poet of Psalms 42 and 43 asks his own soul why it is bowed down within him, the same collapse that bends a mourner's body has folded his inner self, and the question is itself an act of hope that turns him back toward God.
The verb carries its heaviest weight in Isaiah's oracles of the Day of the Lord, where the lofty are made low so that the Lord alone is exalted. Here the bowing is done to people, not by them: pride is forced down under judgment, the involuntary opposite of the willing bow people offer to their idols. The same word bends the everlasting hills before God and lays the fortified city in the dust.
One caution built into the word: this is not the ordinary verb for bowing in worship. That is a separate, far more common word. This rarer verb is about sinking and being brought low, and it is never a term for reverent worship.