rocky, barren
磽 centers on land that is hard and unproductive: rocky ground that is barren and yields little.
磽 combines 石 (stone) with 堯, which likely contributes the sound and the idea of high or hard ground, giving the sense of rocky, barren land.
The left side is stone 石, and the right side 堯 looks like piled earth with legs. Imagine a field of stones and hard-packed earth where nothing grows: rocky and barren.
For コウ, picture a barren rocky field so hard that even a strong crow (コウ) can't peck anything from it: crow -> コウ, and the land stays barren.
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stony, fallow land