Pipe dream

Meaning:

A "pipe dream" is a dream that will never come true or that has an extremely low possibility of coming true. We often use this one to talk about someone's plans to do something that we believe strongly will never happen.

Example sentences:

1. It's a pipe dream.
2. Her plan is just a pipe dream.
2. That was a pipe dream.

Example dialogue:

Two friends are talking about another guy's ambitions to play in the NBA.

A: What do you think of his plan to become a professional basketball player?
B: Well, to be honest, I think it's a pipe dream.
A: Why do you say that?
B: Well, first of all, he's not a good basketball player. He's short. And he's almost 30 years old.
A: Yeah, I guess it is a bit of a pipe dream.

Practice:

Have you ever had a pipe dream?