The word "莫非" is formed by combining the character "莫", which functions as a negative particle meaning "do not" or "nothing" and can imply speculation, with "非", meaning "not" or "wrong", used for negation. Together, these two negating characters create a compound adverb where their juxtaposition reinforces a rhetorical or doubting tone, resulting in the meaning "could it be that" or "is it not the case that".