to shear or clip: to cut wool off a flock, or hair off a head, close to the skin
At its core this verb names one plain action: cutting hair or wool off close to the skin with a blade. Most of its uses picture the yearly sheep-shearing, a festive, profitable time when a farmer clipped the wool from his flock and threw a feast for the workers. That setting is behind Nabal's and Absalom's shearing parties, and it gives Isaiah his famous picture of a silent sheep before those who shear it.
The same verb turns from animals to people when a man takes a blade to his own head. When Job hears his children are dead he tears his robe and shears his head; the prophets order a grieving Jerusalem to shear off her hair. Cutting the hair this way was a raw, public sign of mourning or shock, and the word for clipping a sheep is exactly the word used for it.
Once, in Nahum, the action is turned into a figure of speech: a mighty army, however large, will be sheared off and pass away, the way wool is stripped from a sheep. The bridge across all three uses is the single image of a blade taking hair or wool right down to the skin, whether on a sheep, on a mourner's head, or over a doomed people. A near neighbor, גָּלַח, covers scraping the skin fully clean with a razor rather than clipping it close.