Antediluvian. This adjective means “very old or old-fashioned”or “extremely primitive or outmoded.” So much so that its meaning in Latin is “before the flood.” As in that Old Testament one with Noah.
Here are some examples of its use around the Web:
From the Denver Post: It’s not easy updating a product whose heyday seems antediluvian to today’s eater, and Big Food has struggled.
From Management Today: My big worry is that our bewigged and antediluvian CEO Linton Spivey volunteered to go on the course last week to ‘refresh’ his working knowledge of IT.
Lastly, from Spalding Today: “I approached all four local lodges of the Royal Antediluvian Order of Buffaloes in the area who have given their full backing, together with a sizeable donation. …
Instead of spending the rest of your day pondering what the Royal Antediluvian Order of Buffaloes might be, try using “antediluvian” in a sentence. I swear you won’t sound outmoded at all 😉