A rag is a small piece of old cloth. People use it to clean things or wipe dirt.
She used a rag to clean the table.
He wiped the dust with an old rag.
Sometimes rag means a newspaper or magazine. It often means a paper that is not very good or has gossip.
He reads the morning rag for news.
That rag printed many false stories.
As a verb, rag means to speak badly about someone. It means to criticize or scold them a lot.
They ragged him for his mistake.
The coach ragged the team after losing.
Rag can also mean to tease someone in a fun way. It is a kind of joking that may annoy but is friendly.
They ragged him about his new haircut.
She ragged her brother for forgetting keys.
In the UK, rag means a student event with parades and jokes. It often raises money for charity.
The university held a rag last weekend.
Students joined the rag for charity money.