“‘Perambulate’ — walking for pleasure.” - u/KnotKarma

“‘Somnambulate,’ which is sleepwalking.” - u/ZSAD13

“‘Pantaloons.’ There’d probably have to be a wild shift in fashion first, but still…” - u/TheUnblinkingEye1001

“‘Defenestration’ — the act of throwing something or someone out of a window.” - u/TimeTraveler3056

“‘Clement,’ which means ‘mild’ and is most often used as an adjective to describe weather. We use ‘inclement weather’ all the time, so why not ‘clement weather?’” - u/atreeofnight

“‘Antediluvian’ — meaning archaic or old, as in before the flood (i.e., that of Noah’s Ark).” - u/ebaylus

“‘Gloam’ — it is the blue darkness that follows sunset but comes before the true darkness of nightfall.” - u/ilessthanthreekarate

“‘Uht’ (Old English) — the hour before sunrise.” - u/jondru

“My grandma called umbrellas ‘bumbershoots.’ That is a way more fun word than ‘umbrella.’” - u/Thirty_Helens_Agree

“‘Aglet.’ That’s what the end of a shoelace is called, but I never hear it being used.” - u/orangeheatt

“‘Boondoggle.’ Something that is a waste of time but has the appearance of being practical.” - u/aloha_skye

“‘Pulchritude.’ An ugly word meaning beauty.” - u/DasBloat

“‘Overmorrow’/‘ereyesterday’ are just easier to say than ‘the day after tomorrow’/‘the day before yesterday.’” - u/cantbamistake

“‘Boustrophedon’ — as the ox plows. It describes a numbering or writing system that goes left to right, then right to left.” - u/ColonelMoseby

“‘Sunder’ (verb) and ‘asunder’ (adverb). About the only time you encounter them nowadays is in formal settings, especially religious settings.” - u/balthazar_blue

“The word ‘dingbat.’ It was used up until like the 1950s to describe someone who was acting foolish . . . but it used to mean an an alcoholic drink of unknown ingredients.” - u/LazyUserName74

“I love the word ‘niblings’ (a gender-neutral word for nephews and nieces).” - u/emkatheriine

“‘Swan’ — not the bird, but as in ‘he swanned around the office as if he hadn’t a care in the world.’” - u/JennH19

“‘Prandicle’ — a small meal.” - u/theshortlady

“If I could throw in an Old English word I wish we used, ‘bōchord’ or ‘bochord’ — a library or collection of books (essentially, ‘book’ plus ‘hoard’).” - u/KarmaKitty4-3

“‘Sesquipedalian,’ which means a ‘word with six feet’ — i.e., a very long word.” - u/mkaibear

“‘Zounds.’ It basically means ‘by God’s wounds,’ but it used to be extremely vulgar.” - u/RedWestern

“Back in the ’20s, the term for mocking someone who was full of baloney was ‘applesauce.’” - u/Black_Leopard1904

“Sublime, a word that describes how pain and terror can be associated with delight. In Gothic literature, sublime and beauty are not the same concept: beauty comes from aesthetically pleasing things, while the sublime, coming from fear, is considered far superior.” - u/misatocazzoragi

“‘Coolth.’ It’s the opposite of warmth, and I don’t know why we don’t use it anymore. It’s a good word.” - u/Oscarmaiajonah