IG meaning in Military and Defence ?

An imperial guard or palace guard is a special group of troops (or a member thereof) of an empire, typically closely associated directly with the Emperor or Empress. Usually these troops embody a more elite status than other imperial forces, including the regular armed forces, and maintain special rights, privileges and traditions.

Because the head of state often wishes to be protected by the best soldiers available, their numbers and organisation may be expanded to carry out additional tasks. Napoleon's Imperial Guard is an example of this.

In heterogeneous polities reliant on a greater degree of coercion to maintain central authority the political reliability and loyalty of the guard is the most important factor in their recruitment. In such cases the ranks of the guard may be filled with on the one hand Royal kinsman and clansman with a stake in the survival of the ruling family, and on the other with members socially and culturally divorced from the general population and therefore reliant on Imperial patronage for their survival, for example the Varangian Guards (recruiting solely foreigners), and the Janissaries (Christian children taken as slaves from childhood, to serve the Sultan).

In the post-colonial period, the term has been used colloquially and derisively to describe the staff of a person, usually a politician or corporate executive officer, that acts to prevent direct communication with the person.