Hnolku is
definitely a slang term, being the name of a
very recent traitor to the Caldari State. Compare it to
quisling. Without an accompanying etymological explanation, future generations of English speakers (indeed, current ones) will use that term as a synonym for traitor in ignorance of it actually being someone's name. I think whoever first put forward
hnolku as Caldari for "traitor" was going for the exact same thing, but it's only been a few years since the Insorum scandal involving the traitorous Hnolkus (YC107).
Your average Caldari citizen then would use the word knowing full well its origin, and I think it would be reserved for someone particularly vile (or as I wrote in the current version of the primer, specifically for a contemporary traitor to the modern State). So, it's not a proper synonym quite yet, but it will become one someday. To give us an "original" term:
gaaira n. traitor
agatiri v. to betray (root:
agatir "betray")
agatirone n. betrayal (root:
agatir "betray")
I'll put these in the next time I update the primer.