The Collaborative International Dictionary of English v.0.48:

Officeholder \Of"fice*hold"er\, n.
   One who holds an office; an officer, particularly one in the
   civil service; a placeman.
   [1913 Webster]

WordNet (r) 3.0 (2006):

officeholder
    n 1: someone who is appointed or elected to an office and who
         holds a position of trust; "he is an officer of the court";
         "the club elected its officers for the coming year" [syn:
         officeholder, officer]
    2: the official who holds an office [syn: incumbent,
       officeholder]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "officeholder":
   bureaucrat, civil servant, functionary, functionnaire, holdover,
   incumbent, ins, jack-in-office, lame duck, mandarin, new broom,
   office-bearer, officer, official, officiary, petty tyrant,
   placeman, president-elect, public official, public servant,
   red-tapist