You use someone or somebody to refer to a person without saying exactly who you mean.
双语例句
例：
Her father was shot by someone trying to rob his shop.
她父亲被一个企图抢劫他商店的人开枪打中了。
例：
I need someone to help me.
我需要有人帮忙。
2.?重要人物
If you say that a person is someone or somebody in a particular kind of work or in a particular place, you mean that they are considered to be important in that kind of work or in that place.
双语例句
例：
'Before she came on the scene,' she says, 'I was somebody in this town.'