Idioms with MEAN

I mean
used to correct what you have just said
Let’s ask Bob. I mean Rob.

I mean
used to add a comment or explain what you have just said
We can’t do that! I mean, it’s ridiculous.

mean well
to have good intentions
He can be annoying but he means well.

mean nothing
to have no importance
Money means nothing to them.

mean business
to be serious about doing something
They are starting to realise that he means business.