lather

Concise Oxford English Dictionary © 2008 Oxford University Press:
lather /ˈlɑːðə, ˈlaðə/

▶noun

• 1 a frothy white mass of bubbles produced by soap when mixed with water.

• 2 heavy sweat visible on a horse's coat as a white foam.

• 3 (a lather) informal a state of agitation or nervous excitement.

▶verb

• 1 form or cause to form a lather.

  ■ rub with soap until a lather is produced.

• 2 cover or spread liberally with (a substance).

• 3 informal thrash (someone).

– derivatives
lathery adjective.

– origin OE læthor, lēthran (v.), of Gmc origin.