The word 没事 is formed by directly combining the concept of negation or absence (没) with the concept of an affair, matter, or trouble (事). This creates a literal, conceptual meaning of "there is no matter" or "nothing is happening". Over time, this concrete idea was naturally applied in social contexts to soften interactions, transforming from a simple statement of fact into a versatile phrase used to dismiss minor issues, respond to thanks, or assure someone that a situation is not troublesome. Its formation is essentially the fusion of "absence" and "matter" to convey the broader idea of "no problem".