>I'm a lot more interested in why someone who was looking for and cataloguing 'preposterous' words would have included this one...

you should also consider the possibility, ridiculous as it might seem to you knowing Josefa as you do, that it was just a joke, it being the last word and being, according to some testimony here, just about as preposterous as you can get. also, in *conclusion, the third definition seems odd somehow--why do you suppose that she chose to disinclude that?