The meaning and origin of the expression: Bone idle

Bone idle

What's the origin of the phrase 'Bone idle'?

Robert Forby didn't quite define 'bone idle' in his glossary The Vocabulary Of East Anglia, 1830, but he dcame very close:

"Bone-lazy, bone-sore, bone-tired, adj. so lazy, sore, or tired, that the laziness, the soreness, or the fatigue, seem to have penetrated the very bones."

(Note: Forby also provided the earliest known definition of 'bone dry' in the same work, although the two terms are unrelated).

The earliest citation that I can find of the precise 'bone idle' phrase comes from Thomas Carlyle's New Letters, 1836:

"For the last three weeks I have been going what you call bone-idle."

Another early citation that is worth including for the interesting Yorkshire dialect words 'slake' and 'rauk', is The Dialect of Leeds and Its Neighbourhood: by C. Clough Robinson, 1862:

SLAKE. Badly-washed things are "just slaked ower." A "bone-idle" youth takes a wet towel and "slakes" over his face instead of washing himself properly, leaving a "rauk" from ear to ear, or visible line of demarcation, and having, as an observant comrade remarks, "a neck fit to set tatties in."