gnawing

1. V-T/V-I If people or animals gnaw something or gnaw at it, they bite it repeatedly. 反复啮咬

Woodlice attack living plants and gnaw at the stems. 木虱会侵袭活体植物并不停地啮咬它们的茎。

2. V-I If a feeling or thought gnaws at you, it causes you to keep worrying. 困扰[书面]

...the nagging disquiet that had gnawed at him for days. …困扰了他数日、令他不得安宁的忧虑。