The Collaborative International Dictionary of English v.0.48:

Esquire \Es*quire"\, v. t. [imp. & p. p. Esquired; p. pr. &
   vb. n. Esquiring.]
   To wait on as an esquire or attendant in public; to attend.
   [Colloq.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Esquire \Es*quire"\, n. [OF. escuyer, escuier, properly, a
   shield-bearer, F. ['e]cuyer shield-bearer, armor-bearer,
   squire of a knight, esquire, equerry, rider, horseman, LL.
   scutarius shield-bearer, fr. L. scutum shield, akin to Gr. ?
   skin, hide, from a root meaning to cover; prob. akin to E.
   hide to cover. See Hide to cover, and cf. Equerry,
   Escutcheon.]
   Originally, a shield-bearer or armor-bearer, an attendant on
   a knight; in modern times, a title of dignity next in degree
   below knight and above gentleman; also, a title of office and
   courtesy; -- often shortened to squire.
   [1913 Webster]

   Note: In England, the title of esquire belongs by right of
         birth to the eldest sons of knights and their eldest
         sons in perpetual succession; to the eldest sons of
         younger sons of peers and their eldest sons in
         perpetual succession. It is also given to sheriffs, to
         justices of the peace while in commission, to those who
         bear special office in the royal household, to
         counselors at law, bachelors of divinity, law, or
         physic, and to others. In the United States the title
         is commonly given in courtesy to lawyers and justices
         of the peace, and is often used in the superscription
         of letters instead of Mr.
         [1913 Webster]

WordNet (r) 3.0 (2006):

esquire
    n 1: (Middle Ages) an attendant and shield bearer to a knight; a
         candidate for knighthood
    2: a title of respect for a member of the English gentry ranking
       just below a knight; placed after the name [syn: Esquire,
       Esq]

Moby Thesaurus II by Grady Ward, 1.0:

78 Moby Thesaurus words for "esquire":
   Brahman, Casanova, Don Juan, Lothario, Romeo, amoroso, archduke,
   aristocrat, armiger, baron, baronet, beau, blue blood, bodyguard,
   boyfriend, caballero, cavalier, cavaliere servente, chaperon,
   companion, conductor, convoy, count, daimio, duenna, duke, earl,
   escort, fellow, fellow traveler, flame, gallant, gentleman, gigolo,
   grand duke, grandee, guard, hidalgo, inamorato, lace-curtain,
   lady-killer, laird, landgrave, lord, lordling, love-maker, magnate,
   magnifico, man, margrave, marquis, necker, noble, nobleman,
   old man, optimate, palsgrave, patrician, peer, petter, philanderer,
   safe-conduct, seducer, seigneur, seignior, sheik, shepherd,
   silk-stocking, squire, sugar daddy, swain, swell, thoroughbred,
   upper-cruster, usher, viscount, waldgrave, young man