The word 投入 is formed by combining two individual characters, each contributing a core action to create a new, composite meaning. The first character, 投 (tóu), carries the fundamental idea of "to throw" or "to cast". The second, 入 (rù), means "to enter" or "to go into". When joined, their literal images merge into the conceptual metaphor of "throwing oneself into" an endeavor, visually and notionally depicting a deep, committed immersion or the allocation of resources into a specific target or activity.