Simplified form of 戔. Depicts two weapons (戈) facing each other. Based on the original meaning "kill", now written as 殘. The current meaning is a phonetic loan.
About
戋, the simplified form of 戔, depicts two 戈 (halberds) facing each other. Its original meaning was "kill", a sense now written as 殘. Today, the character is rarely used independently but serves as a phonetic loan in common characters like 钱 (money) and 浅 (shallow).