Verb: stiffen sti-fun
- Become stiff or stiffer
"He stiffened when he saw his boss enter the room"
- Make stiff or stiffer
"Stiffen the cream by adding gelatine"
- (of laws or regulations) make more restrictive, or impose greater penalties
"stiffen the regulations";
- tighten, tighten up, constrain
Derived forms: stiffens, stiffened, stiffening
Type of: alter, bound, change, confine, limit, modify, restrict, throttle, trammel