Rambling, worthless. “Skamble” is merely a variety of scramble, hence “scambling days,” those days in Lent when no regular meals are provided, but each person “scrambles” or shifts for himself.
“Skimble” is added to give force. (See Reduplicated Words.)
And such a deal of skinble-skamble stuff As put me from my faith.
With such scamble-scemble, spitter-spatter, As puts me cleane beside the money-matter.
Taylor's Workes, ii. 39(1630).
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Skimble-Skamble from Infoplease: