1 [I,T] gnaw (away) (at/on) sth to bite a bone, etc many times with your back teeth 啃（骨头）

2 [I] gnaw (away) at sb to make sb feel worried or frightened over a long period of time 使长期感到担心或害怕: Fear of the future gnawed away at her all the time. 她一直为前途问题担心不已。