The Collaborative International Dictionary of English v.0.48:

Accountant \Ac*count"ant\, n. [Cf. F. accomptant, OF. acontant,
   p. pr.]
   1. One who renders account; one accountable.
      [1913 Webster]

   2. A reckoner.
      [1913 Webster]

   3. One who is skilled in, keeps, or adjusts, accounts; an
      officer in a public office, who has charge of the
      accounts.
      [1913 Webster]

   Accountatn general, the head or superintending accountant
      in certain public offices. Also, formerly, an officer in
      the English court of chancery who received the moneys paid
      into the court, and deposited them in the Bank of England.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Accountant \Ac*count"ant\, a.
   Accountable. [Obs.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

accountant
    n 1: someone who maintains and audits business accounts [syn:
         accountant, comptroller, controller]

Moby Thesaurus II by Grady Ward, 1.0:

62 Moby Thesaurus words for "accountant":
   CA, CPA, abacist, accountant general, actuary, amanuensis,
   archivist, auditor, bank accountant, bank examiner, bookkeeper,
   bursar, calculator, cashier, cashkeeper,
   certified public accountant, chamberlain, chartered accountant,
   clerk, comptroller, computer, controller, cost accountant,
   cost keeper, curator, depositary, depository, documentalist,
   engraver, estimator, figurer, filing clerk, financial officer,
   journalizer, librarian, liquidator, marker, notary, notary public,
   paymaster, prothonotary, purse bearer, purser, receiver, reckoner,
   record clerk, recorder, recordist, register, registrar,
   scorekeeper, scorer, scribe, scrivener, secretary, statistician,
   stenographer, steward, stonecutter, timekeeper, treasurer,
   trustee



Bouvier's Law Dictionary, Revised 6th Ed (1856):

ACCOUNTANT. This word has several significations: 1. One who is versed in
accounts; 2. A person or officer appointed to keep the accounts of a public
company; 3. He who renders to another or to a court a just and detailed
statement of the administration of property which he holds as trustee,
executor, administrator or guardian. Vide 16 Vin. Ab. 155.