Hit

From MUME

Hit and kill are commands that can be used to start a fight. If you are fighting more than one opponent, you can switch between them with the command 'hit <victim>'.

You will experience a short delay after you hit something, its length depending on how heavy your weapon is.

Example:

> hit 2.bear
> kill *orc*

Also consider that killing beings who are "good" (innocent citizens, for example) might make you more evil or might also get you in trouble with the local justice officers.