plank

An exercise holding a rigid, face-down position supported by forearms and toes.

"She held the plank for a full minute."

To perform the plank exercise, holding a rigid body position.

"He planks for five minutes every morning."

An informal, often derogatory, term for a foolish or stupid person.

"Don't be such a plank, think before you act!"

A long, flat, thick piece of timber, typically used for building or flooring.

"They used a sturdy plank to cross the ditch."