Swag had one of the loudest runs in 2010s slang. For a couple of years it was a compliment, a hashtag, a hand gesture and a meme. Then, quite quickly, it was a joke about itself.

The slang sense means style and confidence: the cool, self-assured way someone dresses or carries themselves. Cambridge Dictionary defines it as a fashionable and confident appearance or way of behaving. It is a clipping of swagger, which is far older. Puck asks "What hempen homespuns have we swaggering here" in Shakespeare's A Midsummer Night's Dream.

The modern story runs through hip-hop. Know Your Meme traces the revival of swagger to Jay-Z in 2001, and in 2010 tracks by Soulja Boy and Lil B helped push the short form swag everywhere. Over the next two years it filled social media and image macros, and on 26 December 2011 NPR called it "hip-hop's word of the year".

Saturation brought doubts. In May 2011 the linguist Geoffrey Nunberg suggested it was unlikely to last the way cool has, and within months articles were complaining that people were misusing it. By the middle of the decade it mostly signalled an earlier moment.

Two things outlived the trend. The older meanings of swag, stolen loot and the free promotional goods handed out at events, carry on untouched. And so does a stubborn myth: that swag is an acronym for something like "secretly we are gay". Wiktionary records those expansions as folk etymologies. Swag is just swagger with the end cut off.