The Collaborative International Dictionary of English v.0.48:

Charmer \Charm"er\, n.
   1. One who charms, or has power to charm; one who uses the
      power of enchantment; a magician. --Deut. xviii. 11.
      [1913 Webster]

   2. One who delights and attracts the affections.
      [1913 Webster]

WordNet (r) 3.0 (2006):

charmer
    n 1: someone with an assured and ingratiating manner [syn:
         smoothie, smoothy, sweet talker, charmer]
    2: a person who charms others (usually by personal
       attractiveness) [syn: charmer, beguiler]

Moby Thesaurus II by Grady Ward, 1.0:

128 Moby Thesaurus words for "charmer":
   Artful Dodger, Casanova, Circe, Cleopatra, Don Juan, Euryale,
   Gorgon, Lorelei, Lothario, Machiavel, Machiavelli, Machiavellian,
   Medea, Medusa, Miss America, Parthenope, Philadelphia lawyer,
   Romeo, Siren, Stheno, Yankee horse trader, actor, bamboozler,
   bathing beauty, beau ideal, beaut, beauty, beauty contest winner,
   beauty queen, befuddler, beguiler, belle, bewitcher,
   big-time operator, bunny, con artist, con man, conjurer, coquette,
   counterfeiter, cover girl, crafty rascal, dazzler, deceiver,
   deluder, dissembler, dissimulator, dodger, double-dealer, dream,
   duper, enchanter, enchantress, enticer, entrancer, faker,
   femme fatale, flatterer, flirt, fooler, forger, fox, gay deceiver,
   glib tongue, great beauty, hoaxer, horse trader, hypnotizer,
   inveigler, jilt, jilter, joker, jokester, kidder, knockout,
   lady fair, lady-killer, leg-puller, looker, mage, magian, magician,
   magus, mesmerizer, misleader, model, necromancer, paragon, peach,
   pinup, pinup girl, plagiarist, plagiarizer, playactor,
   practical joker, pussycat, ragger, raving beauty, reigning beauty,
   reynard, role-player, seducer, seductress, sex kitten, shyster,
   siren, slick chick, slick citizen, sly dog, slyboots, smoothie,
   sorcerer, sorceress, spellbinder, spoofer, stunner, sweet talker,
   swindler, tease, teaser, tempter, temptress, trickster, vamp,
   vampire, warlock, wizard, wolf



Easton's 1897 Bible Dictionary:

Charmer
   one who practises serpent-charming (Ps. 58:5; Jer. 8:17; Eccl.
   10:11). It was an early and universal opinion that the most
   venomous reptiles could be made harmless by certain charms or by
   sweet sounds. It is well known that there are jugglers in India
   and in other Eastern lands who practise this art at the present
   day.

     In Isa. 19:3 the word "charmers" is the rendering of the
   Hebrew _'ittim_, meaning, properly, necromancers (R.V. marg.,
   "whisperers"). In Deut. 18:11 the word "charmer" means a dealer
   in spells, especially one who, by binding certain knots, was
   supposed thereby to bind a curse or a blessing on its object. In
   Isa. 3:3 the words "eloquent orator" should be, as in the
   Revised Version, "skilful enchanter."