injure, harm, murder
惎 centers on causing deliberate harm: injuring, damaging, or murdering. The meanings share a core of intentional destructive action.
惎 combines 其 (a winnowing basket, here likely used phonetically) with 心 (heart/mind), suggesting harm or injury as a mental or emotional act. The exact historical development is uncertain.
The top 其 looks like a basket or tool, and the bottom 心 is the heart. Imagine using a sharp tool to injure someone's heart: that's harm or murder.
For キ, picture a key being used to harm someone: key -> キ, and the sharp key injures the heart below.