The word "袅袅婷婷" is formed by combining two reduplicated elements: "袅袅" and "婷婷". Each element consists of a base character repeated for emphasis, with "袅" conveying slenderness or delicacy and "婷" conveying grace or elegance. The repetition intensifies the descriptive quality, and the juxtaposition of both reduplicated forms creates a compound phrase that vividly depicts a graceful, slender appearance.