Sobeit

I am just about done with the books in the Serrano Legacy series, so I'm looking at another series by the same author. Under the description of one of the books I find the word sobeit, and I'm thinking somebody dropped some spaces. So I go to my old reliable dictionary site, Merriam-Webster, and it's gone subscription-only! Bah, so I Google sobeit and I find a several other dictionary sites that list it as a legitimate word, though their definitions leave a little to be desired. One claims it is simply a run together version of the three component words: so+be+it. Another claims it is rare case of the English subjunctive, whatever that is. A third claims it is archaic and the meaning is not quite what you would think. All of which leaves me a little confused. Of course it is still basically the middle of the night, so I'm not quite 100%. I think I'll take the easy way out and just avoid using sobeit.