Green’s Dictionary of Slang

nonsense, rubbish.

1937–84		Partridge DSUE (1984) 1302/2: printers –1888.
1986		R.G. Barrett Real Thing 112: Talking the general waffle old football mates talk about when they get together.
1999		Guardian 20 July 23: Time is up for world-class waffle.
1999		R.G. Barrett Wind & Monkey (2013) [ebook] Les brushed the talkback waffle and slipped in a cassette.
2000		Observer Mag. 12 Mar. 10: Fucking waffle.
2000		R.G. Barrett Leaving Bondi (2013) [ebook] There was waffle and moving dialogie and in the end you’re left hanging.
2015		L. McInerney Glorious Heresies 32: [D]ebts he’d conjured out of bloated waffle.