Green’s Dictionary of Slang

giffle gaffle n.

[? dial. jiffle, shuffling, confusion]

nonsense.

[UK]Hotten Dict. of Modern Sl. etc. (2nd edn).
[UK]Hotten Sl. Dict.
[UK]Sl. Dict.
[Scot](ref. to 1870s) Dundee Courier 6 Apr. 6/3: Slang 60 Years Ago [...] Nonsense was ‘giffle-gaffle’.