MEANING: noun:
1. Lack of energy.
2. The lack of an immune response to a foreign substance.

ETYMOLOGY: From an- (not) + ergon (work). Earliest documented use: 1890. The opposite of sense 1 is energy and the opposite of sense 2, allergy. Earliest documented use: 1890.

ANERGO - similar to a wherefore, a hence, and a therefore

IANERGY - what gives the original James Bond novels their drive

AN URGY - emphatic suggestion of importance and a need for promptness