WordWeb Online

1. Pluck or pull at with the fingers
   - pluck at, pull at
    
2. Eat only small pieces of food at a time
   "The anorexic girl just picks at her food";
   - peck at, peck [informal]
    
3. Express a negative opinion of
   "She picked at her student's efforts";
   - disparage, belittle

Derived forms: picking at, picked at, picks at

Type of: criticise [Brit], criticize, damn [informal], eat, knock [informal], pick apart, pull

Antonym: flatter