The word 假设 is formed through the semantic combination of its two constituent characters: 假, which carries the meaning of "false", "temporary", or "hypothetical", and 设, which means "to set up" or "to establish". The compound thus conceptually fuses these ideas to express the act of "setting up a hypothetical (premise)", effectively creating a new, unified meaning for proposing a supposition or making an assumption for the sake of argument or investigation.