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stiffen

1 ENTRIES FOUND:
stiffen /ˈstɪfən/ verb
stiffens; stiffened; stiffening
stiffen
/ˈstɪfən/
verb
stiffens; stiffened; stiffening
Britannica Dictionary definition of STIFFEN
[no object] : to stop moving and become completely still especially because of fear, anger, etc.
[no object] : to become painful to move or use often + up
: to become more severe or strong or to make (something) more severe or strong
[no object]
[+ object]
[+ object] : to make (something, such as cloth) difficult to bend or move

— stiffener

/ˈstɪfənɚ/ noun, plural stiffeners [count]