(it) doesn't matter

1. It makes no difference; that is not relevant or has no bearing (to or on what's being discussed). A: "Why do I have to go through these safety protocols every single time? I didn't come in contact with any hazardous materials!" B: "Doesn't matter. The protocols are there to keep everyone in this lab safe." A: "But I don't want to do my chores!" B: "It doesn't matter what you want! If you don't do your chores, you don't get to see your friends this weekend. End of discussion." You were planning to bring the car back before we woke up? Doesn't matter—what matters is that you took the car for a joyride in the middle of the night without our permission!

2. It is not worth your concern; don't worry about it. A: "Sorry I didn't call you back. I've just been so busy with work." B: "No worries, doesn't matter. I was just calling to see how you're doing." A: "Uh oh, I think I broke it!" B: "It's all right, it doesn't matter—we'll just go to the store and get a new one." Oh, it doesn't matter if you can't make it on Friday—attendance isn't mandatory or anything.

3. It is not worth your attention; forget about it. A: "Go ahead, what were you going to say?" B: "No, it doesn't matter." There's one other issue I wanted to mention. Actually, you know what—doesn't matter. It's getting late, so let's just wrap the meeting up for today. A: "Sorry, what was that? I didn't hear you." B: "Oh, it doesn't matter, it was dumb anyways."