ADJ.
deliberate
VERB + ARCHAISM
isn't
noun
The adoption or imitation of archaic words or style.
An archaic word, style, etc.
In this text, the word "methinks" appears to be a deliberate archaism.
He had the fastidiousness, the preciosity, the love of archaisms, of your true decadent.
noun — the use of an archaic expression
This is an archaism.
Isn't that an archaism?