stiffen

1 of 2

verb

stiff·​en ˈsti-fən 

stiffened; stiffening ˈsti-fə-niŋ 

ˈstif-niŋ

transitive verb

: to make stiff or stiffer

intransitive verb

: to become stiff or stiffer

stiffener

ˈsti-fə-nər 

ˈstif-nər

noun

stiffener

2 of 2

noun

stiff·​en·​er -f(ə)nə(r) 

plural -s

: one that stiffens: such as

a

: a worker who sizes hats

b

: something (such as buckram or a piece of paperboard) used for stiffening a manufactured article

specifically : counter entry 5 sense 5

c

: any of a number of vertical angles secured at intervals across the entire width of the web of a large plate girder to prevent buckling

d

: an angle iron, channel, or other structural shape used to increase the rigidity of plating on a ship's bulkhead

called also stiffening bar

e

: a structural member other than a flat sheet used to reinforce the frame of an aircraft compare stringer

f

: an alcoholic bracer

Synonyms of stiffen

Verb

• strengthen

Examples of stiffen in a Sentence

Verb

She stiffened when he grabbed her shoulder.

The dogs stiffened in alarm.

The law would stiffen penalties for tax evasion.

Recent Examples on the Web

Verb

Major media companies operating traditional linear networks have been under pressure in recent years amid stiffening competition from large tech rivals as programming migrates to streaming. — Dade Hayes, Deadline, 18 June 2026

To execute its ruthless 66-pound weight loss program, the rear seats have been completely deleted, replaced by a massive structural strut brace that significantly stiffens the chassis. — Peter Lyon, Forbes.com, 13 June 2026

Nicks on the edge or stiffened, curled rubber will leave streaks. — Mary Marlowe Leverette, Southern Living, 12 June 2026

The moose flinched and stiffened. — Fred Bear, Outdoor Life, 11 June 2026

Word History

First Known Use

Verb

15th century, in the meaning defined at transitive sense

Rhymes for stiffen

• griffon
• gryphon
• tiffin

Kids Definition

stiffen

verb

stiff·​en ˈstif-ən 

stiffened; stiffening -(ə-)niŋ 

: to make or become stiff or stiffer

stiffener

-(ə-)nər 

noun