The term "nag" is a verb that means to persistently annoy or harass someone with repeated questions, complaints, or demands. It can also refer to an unpleasant habitual complainer who bothers others with their constant chatter or requests.
Usage examples
My mom always nags me to clean my room.
Don't nag your brother about finishing his homework; let him do it at his own pace.
I can't stand it when my neighbor nags me about parking my car in front of his house.
The coach constantly nags the team about running faster and giving their best effort in practice.
My little sister always nags me to play with her dolls, even though I'm not interested.