The structure is a powerful repetition: [Not Finished] + [Not Ended]. This A-B-A-C pattern emphasizes the cyclical, unending nature of the situation. It literally translates to “no finish, no end,” which perfectly captures its meaning.
`没完没了` is a cornerstone of daily conversational complaints in China. While Chinese culture often values harmony and avoiding direct confrontation, this idiom provides a socially acceptable way to express strong frustration and impatience. Saying someone is talking `没完没了` is a bit softer and more descriptive than bluntly telling them to “shut up,” but the underlying annoyance is crystal clear.
This term is highly common in informal, everyday situations.