I am looking for the meaning of these two phrases in the following sentences. Would you please help me with that?
1. He could "sing circles around" most of his contemporaries
2. ... who was supposed to be "wasting away from consumption"
To run circles around some one means to be much better at something. The metaphor is that if you were in a foot race with some one then you could beat him even if you had to do it while running circles around him. The verb run can be replaced by any verb describing a competitive activity. Sing circles...paint circles...dive circles...etc.
Consumptionis an archaic way of describing tuberculosis or a similar disease that consumes the body from within. Wasting away means losing weight and energy.