Noun
black mark (plural black marks)
(idiomatic) something that negatively affects someone's reputation
You should be allowed to rub out and start again, it means that you are human. The purists are tedious, they tell you a mistake is like an enduring black mark. Nonsense -- better to be human than some infernal machine never going wrong. Peter Greenaway
The cool wind blew in my face and all at once I felt as if I had shed dullness from myself. Before me lay a long gray line with a black mark down the center. The birds were singing. It was spring. Burl Ives
When you don't work for a while, immediately you get a little black mark next to your name. Lori Loughlin
He was obviously a very arrogant ragamuffin, and younger than she was, to boot. And he was wearing a necromancer's bells! Apart from that, he was quite handsome, which was another black mark as far as she was concerned. Garth Nix
In some respects, inside information is a form of financial steroid. It is unfair: it is offensive; it is unlawful; and it puts a black mark on the entire enterprise. Preet Bharara
Despite this black mark, Tycho also began corresponding with Kepler, starting with a harsh but legitimate critique of Kepler's system; among a host of objections, Tycho took issue with the use of inaccurate numerical data taken from Copernicus. Source: Internet