1. a ridged board formerly used for washing clothes by rubbing them against it
Usage: historical
2. a road surface with many ridges and bumps
Usage: informal
3. well-defined abdominal muscles with visible ridges
Usage: informal

1. having a ridged or bumpy surface

Examples

• My grandmother used a washboard to clean clothes before washing machines existed.
• The dirt road was so rough it felt like driving on a washboard.
• After months of exercise, he developed washboard abs.
• The washboard surface of the old wooden deck needed sanding.
• She found an antique washboard at the flea market.
• The washboard road made the car shake violently.
• His washboard stomach was the result of daily sit-ups.