Having a bone structure that is light with respect to the surrounding flesh(adjective)
WordNet. Princeton University. 2010.
Use "light-boned" in a sentence
"A thoughtful and attractive woman, small, light-boned, and watchful, Ita was casually dressed in jeans and a cotton blouse."
"Gwyllyn was an insignificant-looking man, light-boned and mousy-haired, but you didn't see him once he began to sing."
"Often he forgot how small she was, how light-boned and fragile, but at times like thistimes when he wanted to put his arms around herhe was restrained by the thought that holding her too hard might hurt her, especially now when he no longer knew his own strength."