buĉi

Buĉi is transitive and specific: it is killing an animal for meat, in the matter-of-fact register a farm or a butcher's shop uses. It is not the general word for killing, which is mortigi, and it is not a word for violence against people unless you are deliberately reaching for the shock of the metaphor.

The derivations are exactly the ones you would predict. Buĉisto is the butcher, the person whose trade this is. Buĉejo is the place, an abattoir. Buĉaĵo is the meat as a product. And amasbuĉi, built on amaso, is to massacre, which is the one place the root is applied to people and where the ugliness is the point.

Its neighbours in the meat vocabulary are already on the site: bovo the ox, porko the pig, ŝafo the sheep and tranĉi the cutting. Esperanto does not copy the English trick where the animal is Anglo-Saxon and the meat on the plate is Norman French, so there is no beef/cow split to learn: bova viando is beef, and the pig stays a pig all the way to the table.