COOF
COOF is an acronym that originated on the Berk List to designate long-time members of the list. It stands for "Crotchety Old Old Fart." It has also been translated by David Spitzley as the much more polite and respectful "Child Of Our Founders."
Today, COOF status is not restricted to members of the Berk List. One cannot become a COOF simply by claiming to be one. The honor is bestowed by the fan community.