A noise emitted from putting too much emphasis on wooly, as in a wooly sweater. It came from the Mortal Kombat character Quan Chi, who shouts it as while he does one of his moves.
Woolay is a word you may shout, and nobody will understand it except people who also played as quan chi for more than five minutes. It may also be used as a battle cry before doing something.
Quan Chi: WOOLAY!
*hypnotizes enemy into snapping their own neck*
*begins running a marathon*