whipstall

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A usually intentional stall in which a small aircraft enters a vertical climb, pauses, slips backward momentarily, then drops nose downward.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A stall of an aircraft in near-vertical climb, followed by slip-back, before the nose turns toward the ground, sometimes an intentional stunt.