While the word gaviscon is commonly attributed to a certain brand of heartburn and indigestion treatments, it has a completely different meaning that has not entered even the simplest of household vernaculars.
1) A ridiculously incompetent or underperforming individual in a particular area,
2) An extremely prevalent disappointment,
3) A person whose vocabulary routinely involves profanity and biological accusation and is generally a cock,
4) Something with low-standards.
1) The way Mary handles spreadsheets is disgusting. I have half a mind to fire that gaviscon.
2) Mate! You see that fookin' goal last night? What a fookin' gaviscon mate!
3) "You all fondle children and **** yourselves in the ****ing ******* you ****ing ******"
"Sod off, you gaviscon."
4) Hello, I'm Jeremy Clarkson, and you're watching Top Gear.