The Star Wars universe has traditionally had some painfully blatant references in the bad guys' names. I was trying to figure out what all the "Darth" titles meant and came up with a few but some are still elusive. (I'm sure most of these have already been discussed somewhere, anyone have a link?)
Darth Nihilus: Okay this is easy, nihilism, the void, hunger
Darth Traya: Sounds sort of like "betrayal" as we know.
Visas Marr (bonus non-Darth name): Presumably this is something about marring vision, which makes sense because she is physically blind.
Darth Vader: "Father" since he's revealed to be Luke's father, but if you know your German (or Indo-European) you might have had a hint in the original movie
Darh Sidious: An insidious threat, of course.
Darth Maul: Violent guy who mauls things.
Darth Revan: A revenant, someone who returns from the dead (or at least a mental death in KOTOR1).
Darth Malak: I'm assuming this is just a generic reference to malice?
Darth Bandon: Remember him from KOTOR1? I don't remember him having a personality other than "end boss" so I can't figure out what thisis supposed to mean. Maybe when he was a child he was abandoned by his parents at the daycare.
Darth Sion: I'm stuck here: how is this supposed to be a reference to pain or shattering?