never mind

idiomatic phrase

—used to tell someone not to be concerned about or give attention to something or someone

Never mind your mistake: it wasn't serious.So you made a little mistake! Never mind (about that): it wasn't serious.'Well, it is a little awkward, for I have a business already,' said I. 'Oh, never mind about that, Mr. Wilson!' said Vincent Spaulding. 'I should be able to look after that for you.'

Arthur Conan DoyleHe would tell Blossom that she might go back to her aunt and never mind about him—he would do very well by himself and he did not blame her in the least.

Lucy Maud Montgomery

—used to say that something previously mentioned or asked can be disregarded

Do you know where my keys are? Oh, never mind. Here they are.

—used to refer to something that is even less likely or possible than something else being mentioned or described

I can barely understand it, never mind explain it.With this knee I can hardly walk, never mind run.Never mind mastering a second language or a subject syllabus, most us have enough difficulty remembering the orders for a round of drinks at the pub.

David Robson