The incumbent is the current holder of an office or position, usually in relation to an election. For example, in an election for president, the incumbent is the person holding or acting in the office of president before the election, whether seeking re-election or not. In some situations, there may not be an incumbent at time of an election for that office or position (for example, when a new electoral division is created), in which case the office or position is regarded as vacant or open.
The word "incumbent" is derived from the Latin verb incumbere, literally meaning "to lean or lay upon" with the present participle stem incumbent-, "leaning a variant of encumber, OED (1989), p. 834 while encumber is derived from the root cumber,OED (1989), p. 218 most appropriately defined: "To occupy obstructively or inconveniently; to block fill up with what hinders freedom of motion or action; to burden, load."OED (1989), p. 124