The word 不过 is formed through the conceptual blending of its two component characters: 不 (bù), meaning "not", and 过 (guò), meaning "to pass" or "to exceed". The core literal idea is "not passing (beyond)", which creates a fundamental sense of limitation or a boundary not being crossed. This concrete notion of restriction evolves metaphorically into expressing a moderating or qualifying sense, meaning "only" or "merely". From this point of limitation, it then naturally extends to a connective function, introducing a statement that contrasts with or concedes to a previous point, hence meaning "but" or "however", as it marks the point where the prior idea does not pass further without amendment.