(transitive) To make stiff. / (intransitive) To become stiff.

Anything added to something in order to stiffen it, such as a support beam, or starch for a collar. / (slang) An alcoholic drink taken to fortify oneself.

plural of stiffener

simple past tense and past participle of stiffen

An item, material or feature that makes something stiffer.

present participle of stiffen

Third-person singular simple present indicative form of stiffen

plural of stiffening

(nautical, historical) A permission granted by the customs department to take cargo or ballast on board before the old cargo is out, in order to steady the ship.

plural of stiffening order