Undrave
Legend
"Hey, I have an idea! Let's start calling FMUs 'gishes'!" and I was like, "That's a terrible idea, please don't do that," but a significant number of people did it.
On the other hand, fighter-mage, fighter/magic-user, spellsword, and the like require essentially no explanation, and don't cause any confusions at all except when talking about specific constructs that may differ between specific game editions.
New proposition: we call them WiFi! Wizard/Fighter