The story
- Latin · derived frombrutum“stupid”
- English todaybrutum fulmen
From Latin brutum (“stupid”) + fulmen (“lightning”), derived from a 1680 pamphlet by Thomas Barlow of that title, originally from a passage of Pliny's Natural History: "hinc bruta fulmina et vana" ("these senseless and ineffectual thunder-claps", intended as a literal description of lightning).
Etymology from Wiktionary, CC BY-SA 4.0.