stiffen

verb ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about stiffen at Wordnik → Where our words come from →

1. Become stiff or stiffer.

   He stiffened when he saw his boss enter the room

2. Make stiff or stiffer.

   Stiffen the cream by adding gelatine

3. Severely restrict in scope or extent.

   tighten the rules