This phrase was first heard by myself when at school many years ago, and it was used by a boy called Thomas, that was his surname, can’t remember his first name. He would deploy this phrase after any long argument to illustrate that he had ‘won’ the argument. To say it was maddening was something of an understatement. He probably became a politician. It’s the old equivalent of the word used by young people today: “whatever:”.
Try using this word at the end of a discussion and see the reaction, it’s probably the same as mine was to that original phrase.
For anyone reading whose first language is not English, then please use either of these tactics sparingly.
There you are then.