What are some of your favorite words that are being used less and less? A few of mine are:
jet set
(JD) juvenile delinquent
hullabaloo
neurotic
next-of-kin
swamp cooler
playpen
rumpus room
the military-industrial complex
fuss-budget
the ecology movement
third-world
katywampus
nonplussed
mortified
pacification
gilded
Source: https://www.slideshare.net/nielrich013/stylistics-26050112