cut, cut flesh from bones
剮 centers on cutting into flesh, especially separating meat from bone. The core idea is a sharp, slicing action that removes or exposes what is underneath.
剮 combines 咼 (a phonetic component suggesting cutting or scraping) with 刂 (knife), forming a character about cutting flesh from bone. The exact historical development of 咼 is uncertain, but the knife radical clearly indicates a cutting action.
The left side 咼 looks like a body part with a mouth-like opening, and the right side 刂 is a knife. Imagine a knife slicing flesh away from a bone, exposing the inner structure.
For カ, picture a carver cutting meat from a bone with a sharp knife: carver -> カ, and the blade slices cleanly.