washboard

noun

1. A board with a corrugated surface against which laundry may be rubbed.
2. Such a board used as a simple percussion instrument.
3. A board fastened along a ship's gunwale to prevent splashing; a splashboard.
4. A stretch of ripples or bumps on a dirt or gravel road caused by interaction between traffic and road surface.

   “washboard road”

   “It's a rough trip no matter how you come, for these washboard roads will loosen up even brandnew cars pretty fast; and hitchhikers always find the going bad.”

   “Franklin is beside himself, revving up the engine in the pickup. As I jump in, he spins out and takes off up the road in the direction the plane came from, bouncing dangerously over washboards and ruts.”

5. (abbreviation, alt-of, colloquial, ellipsis)Ellipsis of washboard abs.
6. (dated)Baseboard; skirting board.

verb

1. To produce a rippled texture on a surface.

   “Doug came up with a half-guilty smile and washboarded his forehead at her.”

   “The rip that was generated by each change of tide had scoured the bottom white and washboarded the sand where it was still layered over the hardpan coral floor.”

   “The low bass brruummmp of 20-mm slugs going out washboarded the bulkheads.”

   “She drove as fast as she dared, braking for the frost heaves that washboarded the blacktop and on her dirt road, bouncing in and out of the clay ruts cut by the flow of runoff.”

2. To play a washboard.

   “It's almost as if the urge to washboard is intrinsically human.”

3. To move up and down or back and forth across the surface of a hive, possibly to lay down a layer of propolis and wax.

   “Individual bees have been observed washboarding on the inside glass of an observation hive.”

   “This behaviour is believed to be associated with general cleaning activities but under what circumstances workers washboard is not known.”