Today’s Grammaricalizanuary entry features an example of a noun becoming less-concrete and taking on adjective-like qualities.

The word in question is hurin, which may refer to either the forehead (as a part of the face) or the frontal bone behind the forehead. As the forehead is the thickest part of the skull, the word hurin comes to mean ‘hard’ or ‘the hardest’. This is a fairly early change in meaning, perhaps -1000 to -800 AT, and may happen under areal influence. At this point, however, hurin is still very much a noun. Only about -400 AT, and in Larlaroł only, is hurin compatible with adjectival morphology, specifically the linking morpheme –(V)t, and by this time the meaning has also drifted, and again only in Larlaroł, to mean ‘center-most, most important’.