The word 殷殷 is formed through reduplication, where the single character 殷, meaning "earnest" or "abundant", is repeated to create a disyllabic term. This duplication intensifies the base meaning, resulting in an adjective or adverb that conveys heightened earnestness or keenness, such as in expressing sincere concern. The formation relies solely on repeating the character to alter its grammatical role and emphasize its semantic core.