Wiktionary
n. (context informal English) The consumption of alcohol with no (or little) food at lunchtime
Wikipedia
"Liquid Lunch" is a song by Caro Emerald. The song was released as a Digital download on 21 May 2013 as the second single from the album The Shocking Miss Emerald (2013). The song has peaked to number 70 on the UK single chart after being BBC Radio 2's playlist in the 'A' List. The song was written by David Schreurs, Vincent DeGiorgio, Jan Van Wieringen, Robin Veldman, Wieger Hoogendorp.
Usage examples of "liquid lunch".
He had had his immortality thrust upon him by an unfortunate accident with an irrational particle accelerator, a liquid lunch and a pair of rubber bands.
Trevor had enjoyed a long midday break at Pete's, then slept off his liquid lunch with an hour nap at his desk, and was just stirring about, making his rounds.
Ryan headed off to the men's room to dump some of his liquid lunch.
He would adjourn to the Swan for a couple of pints of liquid lunch, that was the best thing.
But about five months ago she was here one afternoon with a little redheaded girlfriend, and it had been a long and liquid lunch.