haki

The difference between haki and tranĉi is the motion, and it is worth getting right early. Tranĉi is to cut by drawing a blade through something - bread, paper, cloth. Haki is to cut by striking: an axe into a log, a cleaver into a bone. If the tool goes up before it goes down, the verb is haki.

The tool follows automatically. Hakilo is an axe, built with the -il- suffix for instruments, and once you know haki you never have to learn hakilo separately. Hakita viando is minced meat, dishaki is to chop up into pieces, and hakisto is a woodcutter, though lignohakisto is clearer.

Modern usage has quietly added the computer sense, so haki can mean to hack a system and hakisto a hacker. It is common enough online to recognise but recent enough to be worth avoiding where the context is not obvious - the axe is still the primary reading, and kodrompi (to break into code) is the unambiguous alternative when you need it.