In 5e a "dip" is 1 - 3 levels in a class (prior to 5e a 'dip' was 1-2 levels), a "munchkin" is 3 or more classes of any levels.
Ive never seen anyone ever use 'dip' as meaning anything other then taking just a single lvl. Maybe other groups use the word differently I guess?
Never heard of taking 3 lvls as beeing a munchkin either though, Only know 'Munchkin' as the problem player. And met a fair few of them. Luckily they can easily be identified by their weird builds, although you should check if theyre not just a powergamer. The difference (while sometimes small) can make a big difference in how the player is around the table.
I find it funny though how a topic about Illusionists quikly derailed into wizards in general. And everyone is universally shitting on the Transmuter. And I understand why because their subclass specific features are kinda garbage. Or are so open to interpretation that you have to sit around the table with the DM to even use it. However noone mentions the fact that Transmuters have (by far) the most spells in dnd. So if you just look at the lvl 2 features which makes the spells cheaper to learn can save you a metric arse-ton of cash over the length of a campaign. And generally alot of the spells are quite good as well so people want to pick them up. Like haste, slow, fly, polymorph, etc.
Then again some (like polymorph) are so horribly nerfed or straight up missing in bg3 that im not to sure if its worth taking even for that. I also havent really run into cash problems in the game so how much the savings are worth in terms of 'value' is abit questionable in bg3...
