knuckleball

Etymology
.

Noun

 * 1)  A pitch thrown with the ball gripped on the fingertips and released with no rotation, which travels over an unpredictable path to the plate due to micro-turbulence in the air.
 * Even the pitcher doesn't know where his knuckleball is going.
 * Boston Red Sox pitcher Tim Wakefield is best known for his use of the knuckleball.
 * 1)  An event that is hard to predict.
 * Our vendor keeps throwing us knuckleballs.

Translations

 * Catalan:
 * French: balle-papillon
 * Japanese: ナックル
 * Korean: 너클볼
 * Spanish: lanzamiento de nudillos

Verb

 * 1)  To pitch knuckleballs.