The word "枯燥" is formed by combining the characters "枯" and "燥", both of which independently mean "dry". "枯" typically refers to dryness in the sense of withered or barren, often associated with plants, while "燥" refers to dryness in the sense of arid or lacking moisture, often associated with heat or climate. Together, they create a compound word where their shared meaning of dryness is extended metaphorically to describe something that is dull, monotonous, or uninteresting, as if devoid of vitality or moisture.