The Collaborative International Dictionary of English v.0.48:

Functionary \Func"tion*a*ry\, n.; pl. Functionaries. [Cf. F.
   fonctionnaire.]
   One charged with the performance of a function or office; as,
   a public functionary; secular functionaries.
   [1913 Webster]

WordNet (r) 3.0 (2006):

functionary
    n 1: a worker who holds or is invested with an office [syn:
         official, functionary]

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "functionary":
   Federal, agent, amanuensis, baggage agent, bureaucrat,
   business agent, civil servant, claim agent, clerk,
   commercial agent, commission agent, commissioner, conductor,
   consignee, customer agent, driver, dupe, engineer, factor, fed,
   federal agent, freight agent, functionnaire, general agent,
   handler, implement, instrument, insurance agent, jack-in-office,
   land agent, law agent, literary agent, loan agent, mandarin,
   manipulator, news agent, office-bearer, officeholder, officer,
   official, officiary, operant, operative, operator,
   parliamentary agent, passenger agent, petty tyrant, pilot,
   placeman, press agent, public official, public servant, puppet,
   purchasing agent, real estate agent, red-tapist, runner,
   sales agent, secretary, special agent, station agent, steersman,
   steward, theatrical agent, ticket agent, tool, travel agent,
   walking delegate