n.pl.
1. Brit. a woman's or girl's undergarment covering the body from the waist or hips to the top of the thighs and having leg-holes or separate legs.
2 esp. US a knickerbockers. b a boy's short trousers.
3 (as int.) Brit. sl. an expression of contempt.
Etymology: abbr. of KNICKERBOCKER