> What a variation in meaning - from nun to witch

not really, if you consider one of the translations is "the veiled one" - both nuns and witches (traditionally) wore cloaky-type outfits that would account for the veil descritption

Gaelic can be equally vague and specific. for example, a bit like the Eskimos and their words for snow, there are loads of Gaelic words for hill, each of them referring to a specific kind of hill. so much so that to try and describe the specifics in English might take a long-winded sentence, but in Gaelic it takes just one or two word :)

Cheers
Andy