stiffens; stiffened; stiffening
1
: to stop moving and become completely still especially because of fear, anger, etc.
She stiffened when he grabbed her shoulder.
The dogs stiffened in alarm.
2
: to become painful to move or use
—often + up
My muscles stiffened up the next day.
3
: to become more severe or strong or to make (something) more severe or strong
The wind stiffened.
His resolve has stiffened.
He stiffened his resolve.
The law would stiffen penalties for tax evasion.
4
: to make (something, such as cloth) difficult to bend or move
stiffen a shirt with starch
Cite this Entry
“Stiffen.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/stiffen. Accessed 20 Jun. 2026.
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