高估 (gāo gū) is a verb meaning 'to overestimate' — to judge something or someone as having more value, ability, importance, or likelihood than is actually true. The character 高 (gāo) means 'high' or 'excessive', and 估 (gū) means 'to estimate' or 'to assess'. Together, they literally convey 'estimating too high', capturing the idea of an inflated or unrealistic appraisal.

This word is commonly used in contexts involving judgment, planning, risk assessment, or self-evaluation — for example, when people misjudge their own skills, overrate market demand, or assume others will act in a certain way. It often carries a slightly negative or cautionary tone, implying a lack of objectivity or insufficient evidence. High-frequency collocations include 高估自己 (overestimate oneself), 高估形势 (overestimate the situation), and 高估难度 (overestimate the difficulty).