To ask someone earnestly or humbly for something. She begged him for forgiveness after the argument.
To ask for food or money as charity. The man was seen begging on the street corner every day.
To ask someone to do something in a very urgent or anxious way. He begged her to stay when she was about to leave.
To politely request forgiveness, repetition, or clarification, especially in fixed expressions. "I beg your pardon, could you say that again?"
To assume or take for granted the truth of a premise in an argument, typically in the phrase “beg the question.” By claiming that the law is unnecessary because it will not help, he begs the question of whether help is actually needed.