The easiest way to do this is to find a friend, go to Server List -> Community -> Filters, type in the name of the Server: “Zavod” and choose ZavodTest (or any similar PvP server with close respawns).
Servers change sometimes. You just need to find a server, where you spawn with a weapon. There are lots of them in Community section.
Then take anything in your hand (Pears work too! But it’s better to use something else, because items like pears get destroyed too soon).
After that, beat your friend till he knocks out, and if you’re using a blunt item, beat him till he dies while he’s on the ground so it’ll count as a kill. Make sure your weapon doesn’t get destroyed while finishing him!
On “ZavodTest” server we spawned 10 meters away from each other so the whole achievement took about 15 minutes.