Screwball (noun)

1. A person who is eccentric or behaves in a manner that is unpredictable or irrational.
2. A type of pitch in baseball that has movement that deviates from a normal curve.

Origin:

The origin of the word 'screwball' is uncertain, but it is thought to be a variation of the earlier word 'screwballer' meaning a person who is eccentric or unpredictable. the word has been in use since the late 19th century.

Examples:

1. She was considered a screwball by her classmates because of her unusual habits and quirks.
2. The pitcher was known for his screwball, a pitch that was difficult for hitters to predict.
3. He was always the life of the party, but sometimes his screwball antics got him into trouble.
4. The screwball comic was a hit with audiences because of his off-the-wall humor.
5. The screwball comedy was a popular film genre in the 1930s and 1940s, characterized by wacky, nonsensical plots.