The Chinese idiom "其乐无穷" is formed by the sequential combination of four characters: "其" functions as a possessive pronoun meaning "its", "乐" means "joy", "无" negates with "without", and "穷" means "end". The phrase constructs "其乐" as a nominal subject ("its joy") and "无穷" as a descriptive predicate ("without end"), resulting in a literal meaning that the joy is limitless.