Mummy's boy指的是：很听妈妈的话，什么事情都让母亲来做主，而自己毫无主见的男生或者成年男性。也就是我们常说的“妈宝男”。

【例句】
Don't marry him! He's just a mummy's boy.
别嫁给他！他就是一个妈宝男。

Tim is a mummy's boy. He left his girlfriend because his mother didn't like her.
提姆是一个妈宝男，因为他妈妈不喜欢他的女朋友，所以他离开了对方。