Sentence:  He could see that she was tastefully, though not richly, dressed, and that she walked with an <WSD>elastic</WSD> step that revealed a light heart and the vigor of perfect health. Her face, of course, he could not analyze, since he had caught only the one brief but convincing glimpse of it. 
Meaning of the word marked with <WSD> tags:  springy; bouncy; vivacious