Changing pitch

• It's hard to hit
• A projectile made by chewing a piece of paper and shaping it into a sphere
• Illegal diamond pitch
• Schoolroom missile
• Outlawed baseball pitch
• Cardinal sin?

Wiktionary Word definitions in Wiktionary
n. 1 (context baseball English) A pitch of a baseball that has been partly covered with saliva, illegal at most levels. 2 A balled-up piece of paper, moistened with saliva (by chewing) and shot through a drinking straw. vb. To brainstorm ideas.

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1846 in the schoolboy sense, "bit of paper chewed and rounded as a missile;" 1904 in the baseball sense, from spit (n.1) + ball (n.1).

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
spitball \spit"ball`\, spit ball \spit" ball`\, n. Paper chewed, and rolled into a ball, to be thrown as a missile; -- a childish prank. (Baseball) A pitched ball in throwing which the pitcher grips the ball between two, or three, fingers on one side (which ...

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
noun EXAMPLES FROM CORPUS ▪ Anna said they are the ones who score low grades and throw spitballs in class. ▪ I checked around for spitballs and paper wads. ▪ My memos are spitballs in the face of the faceless monolith where I work. ▪ The Operations students ...