Ruck

Ruck: Ruck, in relation to clothing, describes where the material is scrunched together, either temporarily or permanently. It might even be used to describe pleats. The etymology, as with many fashion metaphorical terms is extended and interesting. Ruck shares its Norse etymology with rick, as used in hayrick, and possibly rick-rack. A ruck or a rick is a pile of stuff, and by analogy, can refer to the masses, the ordinary, much like the hoi polloi (literally: the many). Ruck is used in Rugby to describe a pile-up of players. Thus, ruck is one of those words with a very general root meaning (pile) that has been applied to many different situations. However, this etymology is not shared with rucksack, though it seems applicable. Rucksack has a different etymology (German) and literally means backpack.

His hands slid to her hips, rucking up the hem of her top, to settle against her suede skirt.