The word "置若罔闻" is formed by sequentially combining four characters: 置 (to place), 若 (as if), 罔 (not), and 闻 (to hear). The first two characters, 置若, establish a simile meaning "to place as if", while the last two, 罔闻, negate hearing with "not to hear". This arrangement directly yields the literal meaning "to place as if not hearing", which functions as an idiom denoting deliberate disregard, based solely on the individual meanings and syntactic order of the characters.