imitate, effect, give

效 is composed of 交 (intersect) and 攵 (tap). 交 depicts a person with legs crossed, which extends to mean comparing and imitating. 夂 is a pictograph of a hand holding a stick, implying physical coercion or enforcement. Therefore, 效 means compelling someone with a stick to imitate, and imitating predecessors is a method of learning. Additionally, coercion causes people to learn faster and more accurately, which is why 效 also developed the meaning of efficacy, function, or result.