(all) skin and bones
1. Extremely thin. I know the merger has been stressful, but have you been eating? Because you're all skin and bones these days.
2. Emaciated. The children in the village were skin and bones by the time foreign aid arrived.
nothing but skin and bones and (all) skin and bones
Fig. very thin or emaciated. Bill has lost so much weight. He's nothing but skin and bones. Look at Bill. He's just skin and bones. That old horse is all skin and bones. I won't ride it.
skin and bones
Painfully thin, emaciated. This phrase often is expanded to nothing but skin and bones, as in She came home from her trip nothing but skin and bones. This hyperbolic expression-one could hardly be alive without some flesh-dates from the early 1400s.