From Longman Dictionary of Contemporary Englishdamn alldamn all informal not politeespecially British EnglishNONE/NOTHING nothing at allHe knows damn all about cars. → damn
Examples from the Corpus
damn all• He replied that he knew damn all about it but would swear it was.• She had damn all in the way of information, let alone the illusion of town hall propaganda.• Oh, damn all this killing.• As the mysterious man following Blackeyes, Nigel Planer speaks at last, though he has damn all to say. 