‘代替’ is a verb meaning 'to replace' or 'to take the place of' something or someone, often temporarily or functionally. Though both characters individually can mean 'to substitute' (代 and 替 are near-synonyms), together they form a compound that emphasizes functional substitution rather than permanent replacement — for instance, standing in for someone at work, using one item instead of another, or filling a role when the original is unavailable.

The word is neutral in register and commonly used in both spoken and written Chinese. It typically appears before a noun (e.g., 代替他) or as part of a verb phrase with an object (e.g., 代替这个零件). Unlike ‘替换’ (which implies swapping out an old item for a new one) or ‘取代’ (which suggests supplanting permanently, often with power or authority), ‘代替’ focuses on temporary or situational substitution without implying superiority or permanence.