The word 兴高采烈 is formed by combining two two-character phrases: 兴高, meaning "interest is high", and 采烈, meaning "spirit is intense". Each character contributes directly to this meaning: 兴 (interest), 高 (high), 采 (spirit), and 烈 (intense). Together, they create a fixed idiom denoting a state of high enthusiasm and exuberance.