carpetbagger

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A Northerner who went to the South after the Civil War for political or financial advantage.
2. n. An outsider, especially a politician, who presumptuously seeks a position or success in a new locality.

Century Dictionary and Cyclopedia

1. n. One who travels with a carpet-bag; specifically, a person who takes up his residence in a place, with no more property than he brings in a carpet-bag, with a view of making his way by enterprise.
2. n. In the western United States, a “wildcat” banker, that is, one who had no local abiding-place, and could not be found when wanted. In the Southern States, after the civil war, a new-comer from the North: an opprobrious term applied properly to a class of adventurers who took advantage of the disorganized condition of political affairs in the earlier years of reconstruction to gain control of the public offices and to use their influence over the negro voters for their own selfish ends. The term was often extended to include any unpopular person of Northern origin living in the South.

Wiktionary

1. n. politics, history An immigrant from the Northern to the Southern States after the American Civil War of 1861–5, especially one who went South to gain political influence; hence, someone intervening in the politics of an area with which they are thought to have no real connection.
2. n. pejorative, by extension One who comes to a place or organisation with which they have no previous connection with the sole or primary aim of personal gain, especially political or financial gain.

GNU Webster's 1913

1. n. United States An adventurer; -- a term of contempt for a Northern man seeking private gain or political advancement in the southern part of the United States after the Civil War (1865).

WordNet 3.0

1. n. an outsider who seeks power or success presumptuously