效力

• Pinyin: xiào lì
• Hanzi breakdown: 效 = 交 + 攴 (cross + action — effect/to follow); 力 = pictograph of a flexed arm — force/power

Meaning

Effectiveness; efficacy (noun). Also used as a verb meaning to render service to, or to serve a cause or organisation.

As a noun, 效力 refers to the degree to which something achieves its intended effect — commonly used in legal, medical, and scientific contexts (e.g. 法律效力 = legal force). As a verb, it means to dedicate one's efforts to a person, organisation, or cause, often with a sense of loyalty.

Examples

1. 这份合同自双方签字之日起正式生效，具有完全的法律效力，任何一方不得单方面撤销。 This contract takes effect on the date both parties sign it and carries full legal force; neither side may revoke it unilaterally.
2. 这位学者曾长期效力于多所国际顶尖研究机构，为推动该领域的学术进步作出了卓越贡献。 This scholar served for many years at several of the world’s leading international research institutions, making outstanding contributions to academic progress in the field.
3. 新药的临床试验数据显示，其在治疗该疾病方面的效力远超现有的标准疗法。 Clinical trial data for the new drug show that its effectiveness in treating the disease far exceeds existing standard therapies.

Usage Guide

Context: law, medicine, science, professional service, military

Tone: neutral

Do Say

• 根据国际法，该条约在缔约国之间具有直接适用的法律效力，各方均有义务遵守其条款规定。(Under international law, the treaty has directly applicable legal force between the signatory states — all parties are obligated to comply with its provisions.)
• 他退役后选择以另一种方式继续效力于国家，投身科学研究，为国防技术的发展贡献力量。(After retiring from active duty, he chose to continue serving the nation in a different capacity — devoting himself to scientific research in support of national defence technology development.)

Don't Say

• 这个药效力很强 — while grammatically possible, 效力 as a standalone noun is more natural in formal writing; in casual speech, use 效果好 or 药效强 instead

Origin & History

效 (effect/to serve) + 力 (force/power) — the force of an effect; to devote one's strength to a cause

Cultural Context

Generation: All ages

Social background: Universal