Definition

To make something firm or rigid, often by increasing its stiffness.

Example

The cold weather will stiffen the metal, making it harder to bend.

Tense Forms

Conversation

Did you notice how the cold weather can really stiffen your muscles?

Yeah, I feel it every morning when I wake up.

I should probably stretch more often to prevent that from happening.

Definitely! Stretching helps keep everything flexible and less stiffen.

Synonyms & Antonyms

Root Explanation

Stiffen → It is formed from "stif" (from Old English *stif*, meaning firm or rigid) and "-en" (a suffix used to form verbs indicating to cause to become). The word "stiffen" means to cause something to become firm or rigid.

Memory Tip

Think of making something 'firm' ('stif') — when you 'stiffen' it, you are causing it to become more rigid.

Visually Confused Words