intellectual power; mental capacity; intellect; intelligence
Refers to the faculty of reasoning, understanding, and acquiring knowledge; often used in contexts of mental ability or brainpower.
He excels in intellectual power.
Reading is effective for training the intellect.
頭脳 literally means 'brain' and often refers to intellectual ability in a more concrete or metaphorical sense (e.g., 'brains of the operation'), whereas 知力 is more abstract.
知力 is intellectual or mental power, contrasted with 腕力's reliance on physical force to accomplish something.
Standard kanji spelling; the most common written form.
Rare variant using 智 (wisdom/intellect); not commonly used in modern Japanese.
Compound of 知 (chi, 'knowledge, wisdom') and 力 (ryoku, 'power, strength'). The spelling 智力 uses the older character 智 for 'wisdom', but 知力 is now standard.