An Enchanter is a form of Specialist Wizard in Dungeons & Dragons. Specialized in the school of Enchantment, this is one of those cases where D&D fans are practically talking a different language to other fantasy fans; in most fantasy, "enchanting" is used as the term for transforming mundane items into powerful magical items - but, in D&D, this is the providence of the Artificer. The Enchantment school is instead focused on mind-fuckery; these wizards excel at seizing control of the will of other beings and reducing them to puppets.
Ironically, despite the fact that this is obviously a pretty evil thing to do when you think about it (not to mention a really /d/oor-opening power-set), enchanters traditionally aren't looked upon as evil in D&D - although there was an article in Dragon Magazine pointing out that, if anything, enchanters should be regarded with just as much fear and distrust as Necromancers. There's a reason the Undead Master, a necromancer kit from Advanced Dungeons & Dragons focused on being an archetypical pulp-style evil wizard, is essentially a threeway Conjurer/Enchanter/Necromancer hybrid.
This might be because, after 3rd edition came out, Enchantment took a huge nose-dive in terms of potency; almost every single monster type in the game is immune to Enchantment school spells.
Officially, in Dungeons & Dragons 4th Edition, Specialist Wizards were out of the game, no longer having any mechanical relevance. In practice, the Enchanter was still alive and kicking, because the Wizard's spell-list was full of enchantment-based spells. True, the "utility" spells of old were gone - a player could no longer brute force their way past diplomatic situations with a simple Charm Person or Dominate spell - but the Wizard's attack powers were full of many, many mind-fuckery style spells, to the point of even using "Charm" and "Enchantment" as keywords. With the release of material like the Dragon Magazine article on Feywild-themed wizards and the Arcane Power splatbook, a player could easily build up a full-fledged mind-melting enchanter if they wanted to.
The Enchanter name returned as a subclass for the Mage in Dungeons & Dragons 4th Edition, meaning now you could "officially" be an Enchanter. Being an Enchanter was handled as a set of three features gained by choosing that specific magical school, and which were acquired at levels 1, 5 and 10. A Mage could also dabble in Enchantment by taking the 1st and 5th level Enchantment school benefits at levels 4 and 8.
- Enchantment Apprentice: When one of your arcane enchantment powers allows you to pull, push, or slide a creature, the maximum distance of the forced movement increases by 2 squares.
- Enchantment Expert: You gain a +2 bonus to Bluff checks and Diplomacy checks.
- Enchantment Master: When one of your arcane enchantment powers forces a creature to make an attack, that creature gains a +2 power bonus to the attack roll.
The Essentials Witch class, incidentally, also added a number of new Enchanter spells to the Wizard's arsenal, although it also added many transmutation and illusion spells too.
5th Edition's Arcane Tradition
In Dungeons & Dragons 5th Edition, Enchanters have their ability to hypnotise others enhanced through their specialization; Hypnotic Gaze (2nd level) lets them effectively make a free charm attack on a creature within 5 feet, Instinctive Charm (6th level) lets them try and bewitch an attacker and so redirect its attack as a reaction, Split Enchantment (10th level) lets them hit two creatures with a single 1-target Enchantment spell, and finally, Alter Memories (14th level) lets them not only make a charmed creature unaware of its being charmed, they can also try to blank out its memories of some of the time it spent under their control.