The word 未必 (wèibì), meaning "not necessarily" or "may not", is formed through the logical combination of its two component characters: 未 (wèi), which carries the fundamental meaning of "not yet" or "has not", and 必 (bì), which means "certainly" or "must". When joined, the compound directly and conceptually negates the idea of certainty; it suggests that while something is possible, it is not yet certain or not necessarily so. This structure is a classic example of Chinese word formation where two opposing or modifying morphemes are combined to create a new, nuanced adverbial expression that is more abstract than the sum of its parts, frequently used to express doubt or to soften an absolute statement.