From Longman Dictionary of Contemporary Englishstiffenstiff‧en /ˈstɪfən/ verb 1 [intransitive]UNFRIENDLY if you stiffen, your body suddenly becomes firm, straight, or still because you feel angry or anxious OPP relax He touched her, and she stiffened.2 [intransitive, transitive]DETERMINED to become stronger, more severe, or more determined, or to make something do this a campaign to stiffen rules against drink-driving Their opposition only stiffened my resolve.3 [intransitive] (also stiffen up)HURT/CAUSE PAIN to become painful and difficult to move His joints had stiffened. My back had stiffened up.4 [transitive]BEND# to make material stiff so that it will not bend easily→ See Verb table
Examples from the Corpus
stiffen• High school graduation standards must be stiffened.• I had to cut quickly, before the dough stiffened.• You can stiffen curtain fabric by using a special liquid solution.• The very thought stiffened her body in his arms and she all but scowled at him.• It also stiffened his intransigence toward his internal critics, and in turn stiffened their resistance to him.• Then all at once he stiffened, staring again towards the shore.• Leaning back into the hill and stiffening the downhill leg is the worst reaction, if the most instinctive.• Moisture will only stiffen the leather of your shoes.• Point your toes and stiffen the muscles in your legs.• The council wants to stiffen the penalty for drunk driving.• He will stiffen their resistance to cuts in welfare.• Already, Meh'Lindi's own skin seemed to be stiffening under that black second skin.• Nora stiffened when she heard her ex-boyfriend's name mentioned.stiffened ... resolve• He had only to say he admired Grace Bird's fortitude and instantly her chin stiffened with resolve. 