Definition from Wiktionary, the free dictionary
- (euphemistic) A recent war, especially the American Civil War.
- With membership limited strictly to "veterans of the late unpleasantness," the GAR encouraged the formation of Allied Orders to aid them in its various works. — Sons of Union Veterans of the Civil War, Brief History of the Grand Army of the Republic 
- 2003: It is unlikely that anyone with significant knowledge of the Army or the late unpleasantness in Southeast Asia, upon reading these two sentences, would respond other than with a scatological barnyard expletive or some more genteel utterance representing the same level of acceptance. — Zane E. Finkelstein (referring to the Vietnam War)