Green’s Dictionary of Slang

1. a knockout blow, thus v. ferricadouze, lit. or fig, knock out, to overwhelm.

1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 228/1: No fear of a ferricadouzer for the butcher. [...] What does it mean? It means a dewskitch (a good thrashing).
1864, 1867, 1870		Hotten Sl. Dict.
1882		Sydney Sl. Dict. (2 edn) 4: Ferricadouzer - A knock-down blow (cor. Italian).
2019		P. Baker Fabulosa 292/1: ferricadooza a knock-down blow.
2023		R. Milward Man-Eating Typewriter 57: [A] flapper or purring-cheet ferricadoozed by a malnourished fox.

2. (also fericadooza) also in fig. use, anything outstanding or overwhelming.

1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 424/2: Oh! it does give them a ferrycadouzer.
2002		Juha ‘Polari’ 🎵 on Polari [album] Beach in the screech. Alamo jo! / This dizzy hoofer gonna dowry jeebo. / Varda me fatcha, meshigner bona. / Savvy you gettin fericadooza.
2005		posting at http://johnreppion.proboards33.com 8 Dec. 🌐 Did you varda that fericadooza review screeved by that old maunged fruit of an omi-paloni tv critic in The Mail? That Pogy poncette had the cod temerity to call us ‘no more menacing than a bunch of outsized orchids left over from The Muppet Show’, the manky-eeked aspro!