浓浓 is a reduplicated form of 浓 (nóng, 'thick, strong, dense'). The reduplication intensifies the quality, often conveying a sense of richness, depth, or abundance — used for smells (浓浓的咖啡香), emotions (浓浓的爱意), or atmosphere (浓浓的年味). It is an adjective-like adverb (POS z) that typically modifies nouns or verbs, and is common in literary or descriptive writing.