pick at something

Từ điển Oxford Advanced Learner 8th

ˈpick at sth derived
1. to eat food slowly, taking small amounts or bites because you are not hungry
•She sat at the table in silence, picking at her dinner.
2. to pull or touch sth several times
•He tried to undo the knot by picking at it with his fingers.
Main entry: ↑pick_derived