I cannot understand why BE skiver (apparently a variant of skewer) has the meaning of slacker/ loafer/lazybones, whereas BE skivvy or skivey is an overworked domestic servant, a drudge - a diametrically opposite concept.Skiver is said to derive from an Old Norse root containing the idea of cut, slice or disc(disk): the skiver cuts off thick slices of time and effort from what he owes his employer. I can find no etymology for skivvy/skivey so it may somehow share the same origin as skiver. The same ON root has also given us shear, share and score , even shire, I think.
The AE and nautical skivvies means underwear, possibly because such garments are skimpy, looking as if almost cut to shreds, especially in the case of a string vest, a possible explanation being another derivative of the same root, shiver, as in "Shiver me (my) timbers!" where shiver means shatter, but I may be fantasising.
My main point is: how can one explain the opposite meanings of British skiver and skivvy/skivey?