Definition of "archaicity"

Most importantly perhaps, it is evident that the impression of archaicity which any reader will experience on reading The Lord of the Rings is partly due to three simple lexical causes: the “overuse” of words borrowed from nineteenth-century fiction (e.g. yonder, journey [v], topmost), the avoidance of words associated with the modern world and the comparatively dense use of new coinages, unusual grammatical patterns, rare or obsolescent words.

2021, Thomas Kullmann and Dirk Siepmann, Tolkien as a Literary Artist: Exploring Rhetoric, Language and Style in The Lord of the Rings, Palgrave-Macmillan 2021