We know for warcraft cosmology that discord/disorder was the progenitor of fel / chaos magic.
We also know that the title of “wizard” is common in the warcraft universe.
That raises the quest, why are warlocks called “Warlock” instead of “Chaos Wizard”, because I feel that the latter is a lot more interesting of a class name.
Can’t say I’ve seen much mention of the word wizard in WoW it’s mainly mage.
As for Warlock, you could probably trace it’s origins back to Daenor since the first 'locks that we see are from there or perhaps the word can be traced further back to a world the Legion conquered. A bit like most words in the English language come from other countries or past civilisations that we have anglicised.
“Wizard’s Sanctum” where all of the portal are located and “I only counted 99 kills, wizard” Kargath’s quote.
Those are the two that come to mind straight away.
They are former wizard’s, or priest’s or anyone who saw legion power and was fascinated by it. Because in lorewise fel was far far more stronger magic than any other type in the game is presented. Dark magic is not allowed(because of it’s destructive wake) by most of azeroth races, so most of them are outcast’s for using it. It is also much more simplier to learn, that’s why u see some primitve mobs or lesser creatures use that magic . Power of user depends how strong he is to master this kind of magic
That means Warlock is something like Dark Wizard