Definitions of lather:

• noun:   the foam resulting from excessive sweating (as on a horse)
• noun:   a workman who puts up laths
• noun:   the froth produced by soaps or detergents
• noun:   agitation resulting from active worry
• verb:   form a lather

  Example: "The shaving cream lathered"

• verb:   cover with soap

  Example: "Lather your body when you shower"

• verb:   rub soap all over, usually with the purpose of cleaning
• verb:   beat severely with a whip or rod
• name:  A surname (very rare: popularity rank in the U.S.: #82247)