The brutalist movement began in the early 1950s under the architect Le Corbusier, who named his style of crude cement buildings beton brut, which literally meant "raw concrete". This term perfectly encapsulated the vibe the structures exuded, and was soon widespread. When the word was borrowed into English in the 1950s, a slight tweak was made to make it more recognizable as an English term, and, lo, we ended up with the word brutalism. So it's a slightly different word and connotation in our language, but, etymologically, none of that matters, as both brut and English brutal come from Latin brutus (albeit the latter by way of Medieval Latin brutalis, "stupid"), meaning "heavy" or "dull". Yes, this is where the name for Caesar's assassin comes from as well. Curiously enough, brutus does not come from Proto-Italic as most Latin words do. Instead, it came through Oscan from the Proto-Indo-European reconstruction gwere, meaning "heavy".
Adam Aleksic, a leading contender for valedictorian of his high school, is a 215-month-old boy with disturbing interests in etymology, vexillology, geography, and law. Adam would like to one day visit Tajikistan and probably isn't spying for the Uzbek government.
The Etymology Nerd