OK Boomer

 This is a put-down from a young person to an old person who is demonstrating that they are out of touch with the contemporary world. The older person doesn’t have to be an actual baby boomer, just someone over forty.

 The phrase has been around for a while but was popularised this year as an internet meme. Perhaps most notably it has been produced in response to Joe Biden’s campaign slogan, No Malarkey, which features on a large bus in which Biden will tour the country. Perhaps he thought he was being folksy but it has come across as out-dated and hopelessly old-fashioned.

 The word malarkey is an Americanism of the 1920s, meaning foolishness or humbug. The OED suggests an origin in an American cartoon of that period. Another possible origin is from English northern dialect. The word marlockmeaning anything from playful foolery to noisy uproar has a derived adjective marlocky. It could be a combination of both, that is, this odd dialectal word just happening to be in the vocabulary of the cartoonist who then made it popular.

 Whatever the origin of the word and whatever the connotations it has for Americans today, it seems to have been dismissed with an OK Boomer!