One of the more graceful
ways of saying, "Holding up the middle finger
Using this gesture is often called obscene, and is not often used in politics. The One fingered salute is sometimes done like a regular salute with the middle finger, or in regular flipping off gesture. Either way, it's sign language for Fuck you.
And the next time someone wonders what the one fingered salute is, show them. But be careful some people will respond to this with a severe beating, flogging, wet towel snapping, or a swift kick in the nuts. Don't say I didn't warn you.