The word "不在乎" is formed by directly adding the negation character "不" (meaning "not") to the verb phrase "在乎" (meaning "to care about" or "to mind"). "在乎" itself combines "在" (originally indicating existence or location) with the classical Chinese particle "乎" (used here to convey a relational or emphatic sense), resulting in a meaning of attaching importance to something. Thus, "不在乎" structurally negates "在乎" to produce the meaning of not caring or being indifferent.