from The Century Dictionary.
- noun A sharp, forward, clever woman.
- noun One who speaks or scolds incessantly.
Sorry, no etymologies found.
Others derive it from the Scotch yankie, meaning a gigantic falsehood.
A military is good and just as long as it keeps the peace and doesn't run roughshod over other groups just because they have the bigger guns. yankie doodle
Edited to add: Your Nam yankie tunnel rat might look ally but his weapon handling skills are gash.