noun
slacks; dress pants
Refers to semi-formal trousers, typically not jeans or casual wear. Often used for men's dress pants in a business or smart-casual context.
彼は新しいスラックスをはいて出かけた。
He went out wearing his new slacks.
Borrowed from English 'slacks', referring to loose-fitting trousers. The exact path into Japanese is uncertain, but it became common in the mid-20th century.