Other forms: stunning, stunned, stuns
To stun is to knock senseless, or to astonish completely. Stun the fish, stunned by the news, a stun grenade.
In slaughter, stunning before killing is a legal requirement in most countries and the point of the rule is that the animal feels nothing. The figurative sense is now the commoner: stunned means astonished, and stunning has drifted all the way to beautiful.
1verbstunTo knock senseless, or to astonish completely.
“The news of his sudden resignation stunned everyone in the office.”
stun is a striking.
Middle English stonen, probably from Old French estoner, from Latin extonare, to strike with thunder. Astonish is a relative.
Proto-Indo-European
*(s)tenh₂-
Frankish
*stunōn — to thunder, crash
Latin
*stunō
Anglo-Norman
estoner — to stun, astonish
Middle English
stonen
English, today
stun
Middle English stonen, stone (“to astonish, stun, numb”), probably either directly or indirectly from Anglo-Norman estoner (“to stun, astonish”), from Latin stunō, from Frankish stunōn (“to thunder, crash”) or perhaps from an unattested extonāre (“to thunder out, make a thunderous sound”), from tonō "to thunder"; compare Latin attono. An alternative etymology derives stonen from Old English stunian (“to smash, thunder”), from Proto-West Germanic stunōn. See also astonish, astound. Compare Swedish stöna (“to moan, groan”), Danish stønne (“to moan, groan”), Icelandic stynja (“to moan”), Occitan estonar (“to surprise”), and French étonner (“to surprise”), and more distantly, Dutch steunen (“to groan; support”), German stöhnen (“to groan, moan”), German staunen (“to be astonished, be amazed, marvel at”), and Russian стонать, стена́ть (“to moan, groan”).
Etymology from Wiktionary, CC BY-SA