1. National Guard.
  2. New Guinea.
  3. no good.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Word Origin and History for n.g.

abbreviation of no good, attested from 1838; variant n.b.g. for no bloody good is first recorded 1903.

Online Etymology Dictionary, © 2010 Douglas Harper