我有几个英语语境中的单词意思不是太确定,希望知道的朋友帮忙确定一下,

我有几个英语语境中的单词意思不是太确定,希望知道的朋友帮忙确定一下,
His brother is a yes-man.I don't like him.
这里yes-man我理解的是“唯唯诺诺的人”,请问这个语境中yes-man到底是什么意思.
The little boy is now at home today.Things are sixs and sevens.
这里的sixs and sevens是“乱七八糟”的意思么?
3.What is "wall has ears".
wall has ears是隔墙有耳的意思吧?