Green’s Dictionary of Slang

indifferently, carelessly.

1860		Hotten Dict. of Modern Sl. etc. (2nd edn).
1870		Hotten Sl. Dict.
1876		Besant & Rice Son of a Vulcan II 186: My father and Jack having been living, not nicely at all, as I expected, but anyhow.
1902		Free Lance 11 Oct. 44 2: I have seen these particular waistcoats made ‘all anyhow’ as regards the matching of the stripe line [F&H].
1923		J. Manchon Le Slang.