When musicians perform unplugged, they play without electric instruments and heavy amplification — acoustic guitars instead of electric ones, a quieter drum kit or none, the singer close to the microphone. The word comes straight from the picture of pulling the plug out of the socket, and it became a music word because of MTV's television series 'MTV Unplugged' in the early 1990s, where famous rock bands sat down and played stripped-back acoustic versions of their own songs. That is why the word carries a whole feeling and not just a fact: unplugged suggests small, intimate, honest, close to the bone — the song with nothing to hide behind. It works as an adjective ('an unplugged set', 'an unplugged album') and as an adverb after the verb ('they played the whole show unplugged'). People also stretch it outside music, half-jokingly, to mean stepping away from screens and devices for a while — 'a weekend unplugged'. And of course the plain original meaning is alive too: an unplugged fridge, an unplugged charger — one whose plug is not in the socket.