1. the fact of optimizing; making the best of anything.
2. the condition of being optimized.
3. Mathematics . a mathematical technique for finding a maximum or minimum value of a function of several variables subject to a set of constraints, as linear programming or systems analysis.
I don't have a decent source to define min/maxing, so I'll use this one: "Increasing a stat or ability while shunting the consequences into areas of the character that have little to no impact."
The classic application of min/maxing is to make a fighter with an 18/x strength, very high constitution and dexterity, and let suffer the intelligence, wisdom, and most of all charisma (used to be referred to as the "throw-away stat"). Even if one is playing a character with both a low intelligence and a low wisdom it's rather unlikely that a player who is making this character is capable of actually roleplaying such a character. Since current character creation guides make this type of character highly difficult to generate I frequently utilize this last problem into what really bothers me most about the practice, making a mechanically viable character that is either internally inconsistent, inconsistent in the gaming world, or inconsistent or impossible to roleplay.
So what's the point? Encounters has a benefit for causing 15+ damage in one attack. There are level 1 character builds in Essentials that can do that easily and regularly, thus that's not a good benchmark for a high-damage threshold. So there are now characters that can be min/maxed for damage, because the resultant character is no longer interally consistant to the game.
"Aggressive Advantage: You gain combat advantage against all enemies during your first turn in an encounter." This one doesn't look too bad, but turn it around. "You're walking through the ruins of a tower, and a group of skeletons jumps out. You're unprepared for the ferocity of the attack, they have combat advantage during the first round. You beat them and open a door: a group of skeletons attacks. You're unprepared for the ferocity of the attack, they have combat advantage during the first round. You beat them, too. Later you spot some skeletons who seem unaware of you. You get a surprise round, then they attack. You're unprepared for the ferocity of the attack, they have combat advantage during the first round." Am I the only one who considers it just wrong that no matter how many times you see the skeletons, no matter how much you try to prepare, nothing can possibly overcome the ferocity of the attack? I disagree.
I want to make a wizard. I like the ranged attacks, the ranged area attacks, the arcane, all of this. But I don't like that if someone gets close to me I have to move away or give up opportunity attacks, so I'll take the feat Staff Expertise. Now I'm a wonderful level 1 wizard, and I shoot magic missle. (A short distance away a level 9 elven archer witnesses this and turns to Corellon, praying for guidance on why if his family has been using bows since the elves were first created in the feywild he still has to deal with how to actually get away from monsters to shoot freely, but yet again receives no reply.) So I made a character that removed the penalty for that character in a way that is not internally consistent in the world.
I hate feats and character builds that mitigate the challenges of the character. I hate seeing combat advantage becoming just some benefit that has nothing to do with imparing your enemies' combat readiness. I hate trying to run a world or a game where the damage output and potential no longer corresponds to what is expected.
The obvious solutions are to limit character builds, adjust the world to compensate, or just get over it. The last is the solution I lean towards most frequently, and feels worst to do.
On the other side is optomization. If someone wants to make an archer, the elf immediately springs to mind either because of a +1 attack with a bow or elven accuracy or any other mechanic that happens to be in place. This is because elves make the best archers, and this is internally consistent in the game, the world, and obviously ease of roleplay. Most character builds are of this nature.