投资 (tóu zī) literally combines 投 (tóu, 'to throw, to put in') and 资 (zī, 'resources, capital, funds'), conveying the idea of 'putting resources into something'—most commonly money, but also time, effort, or energy—with the expectation of future benefit. It is a formal, neutral-term verb used widely in business, finance, education, and personal development contexts.

The word functions as a transitive verb and often appears with objects like money (钱), projects (项目), companies (公司), or fields (领域). It can also serve as a noun meaning 'investment' when preceded by a measure word (e.g., 一笔投资) or in compound nouns (e.g., 投资者 'investor'). Unlike casual terms like 花钱 ('to spend money'), 投资 implies intentionality, planning, and anticipated return—whether financial, social, or personal.