Is a sign of lethality when yer PvPing. Actually, it be a sign of being in the general proximity of lethality, since ya gets credit if the gumpernubber dies near ya, whether you did fer him or not. Which is good fer buggers like me, since in a fight I often tries ta slow, stun, and silence someone so someone else can skillfully stab and and slice and spear (fear mah uber alliteration skillz!).
So, ya put some bugger down, or ya stands there with a dumb look on yer face while the guy next to you does it, and you get an Honorable Kill. And the universe is polite enough to keep track of yer HKs for ya so you don't gots to be bothered. You can look'em up if ya wants - go to yer character sheet and click on the PVP tab and there they be. If ya wants to see how deadly yer friends is, you can go they's armory page and see it there. Me friend Mr. Hoof has over 12,000 kills. Out of Mana Meliadoul has over 23,000. Even Hydra who don't PvP has herself a couple thousand. But then ya go to the armory page of that killing machine Ratshag and there ain't nuthin' said about about Honorable Kills. Is like they don't exist. What the hey?
Is cause the armory don't list yer HKs until you reach the level of worthiness. And they defines worthiness as 1337. And I's only got about 850, so far, which is way more than one, but not enoughs yet. Now, I knows there's a spiritual signifcance to 1337, but there's other spiritually significant numbers. Like 1138, or 42, or 998 (is density of water at Standard Temperature). So how comes they could'na picked one of these others (which be quicker to reach), hmmmm? Then I'd have more bling on me armory page sooners.