The phrase "indelible mark" means leaving a lasting or permanent impression, often referring to an impact or influence that cannot be easily erased or forgotten. Full definition
The movie characterises contemporary figures, willingly being interviewed about their portrayal as part of the movie's publicity (David Frost) and modern historic figures who have left indelible marks on political and cultural discourse (Richard Nixon). (filmireland.net)
Early experiences in life leave indelible marks on our evolving characters. (creativeboom.com)
Part of an impressive class already making indelible marks on the field, the ICFT winners were among the 679 graduates at the 2010 diploma ceremony addressed by McCartney: «You make us hopeful,» she said. (gse.harvard.edu)