Meaning：
to be very determined in stopping something

Synonyms：
Take a firm stand, Assert something strongly

Sentences：

My dad puts his foot down when it comes to my bedtime.

She put her foot down and changed the name of the company.

I finally put my foot down and demanded to talk to someone in charge.

Conversation 1

A: Is your housemate still causing trouble?

B: No, he’s being really good now.

A: Wow, what happened?

B: I put my foot down and told him that if he didn’t start behaving himself I would have him thrown out.

A: Was he angry?

Conversation 2

A: This is the third time you have been late for work this week.

B: Yes I know, I’m very sorry, it won’t happen again.

A: That is what you said last time. Now I am going to put my foot down. If you are late again you will lose your job, do you understand?

B: Yes, I’m very sorry.

Conversation 3

A: Is your boss still making you work late?

B: Yes, almost everyday.

A: Have you asked him for overtime?

B: No, I haven’t

A: Well you should put your foot down and tell him that if he wants you to work late, he’s going to have to pay you.

(callan book stage 7, 705p）