That's the end of that; I've had enough of that. That's it, everyone, thank you for listening. There are refreshments in the other room. That's it! I can't listen to you two fighting anymore, I'm getting out of here!
1. Inf. That does it!; That's the last straw! That's it! I'm leaving! I've had enough! Okay. That's it! I'm going to report you to human resources!
2. That is the answer! That's it! You are right. That's it! You got the right answer.
that’s (about) ˈit(informal)
1 used for saying that an activity, a job, etc. is finished: That’s it for today. We can go home now. ♢ That’s about it. I’ve said all I wanted to say.
2 used to agree with what somebody has just said: ‘You mean you won’t get more than $500 for the job?’ ‘That’s about it.’