Other forms: thudding, thuds
A thud is the sound heavy things make when they land: low, dull and over at once. A book sliding off a table, a sack of potatoes onto the kitchen floor, someone upstairs getting out of bed.
Thud is a noun and a verb at the same time. You hear a thud, and things thud: boots thud on the stairs, a heart thuds in your chest after you have run for the bus or heard a noise downstairs. The sound has no ring in it. Glass smashes, metal clangs, a dropped coin sings, but something solid with soft edges thuds. It sits very close to thump, and the two swap places freely, except that a thump can be a blow you deliver and a thud is only ever a noise something makes. With a thud is the phrase writers reach for, and land with a thud is what a joke does when nobody laughs.
1nounthudA dull, heavy sound, made by something solid landing on a surface.
“The suitcase came off the top shelf and hit the floor with a thud.”
synonyms: thump
2verbfallTo hit or fall against something with that sound.
“Something thudded against the window in the dark.”
3verbheartOf the heart: to beat heavily and loudly.
“She stopped on the landing with her heart thudding.”
Also accepted in games: thump
Thud goes back to Middle English thudden, to strike with a weapon, and before that to Old English þyddan, to strike, press or thrust. Behind those sits a Proto-Germanic verb for pressing and thrusting, and further back a Proto-Indo-European root *tūk-, to beat. So the sound word began as a hitting word: first the blow, then the noise it made.
Proto-Germanic
*þuddijaną
Old English
þyddan — to strike, press, thrust
Middle English
thudden — to strike with a weapon
English, today
thud
Built from
From Middle English thudden (“to strike with a weapon”), from Old English þyddan (“to strike, press, thrust”), from Proto-Germanic þuddijaną, þiudijaną (“to strike, thrust”), from Proto-Germanic þūhaną, þeuhaną (“to press”), from Proto-Indo-European tūk- (“to beat”). Cognate with Old English þoddettan (“to strike, push, batter”), Old English þȳdan (“to strike, stab, thrust, press”), Old English þēowan (“to press”), Albanian thundër (“a hoof, talon, a shaft", figuratively, "oppression, torment”).
Etymology from Wiktionary, CC BY-SA
Practised in Everyday Verbs, Sounds & Noises