foolish, stooped over
佝 centers on a bent, stooped posture, often associated with physical deformity or, by extension, a foolish or simple-minded state. The two meanings connect through the image of a hunched, perhaps simple, figure.
佝 combines the person radical 亻 with 句, which likely contributes a phonetic element. The character is associated with a stooped or bent condition, but the exact historical development is uncertain.
A person 亻 with a hooked, bent shape 句: imagine someone so stooped over that they look foolishly hunched.
For コウ, picture a stooped person coughing (コウ) from the strain of being bent over: cough -> コウ, and the hunched figure struggles to breathe.
rickets