simple past tense and past participle of stiffen

comparative form of stiff: more stiff, more rigid, more inflexible, more unbending.

(slang, vulgar) An erection of the penis.

superlative form of stiff: most stiff Most rigid, most inflexible, most unbending.

An item, material or feature that makes something stiffer.

present participle of stiffen

present participle of stiff

Third-person singular simple present indicative form of stiffen

(dialect) stiff

(computing, rare, derogatory) Software that is inflexible, cannot be customized or upgraded, etc.