2 to become or make something stronger or more difficult: --
3 to become or make something firm or more difficult to bend: --
5 to become nervous and less relaxed: --
I stiffened when I saw him coming toward me.
This study of the creature has convinced scientists involved with smart materials projects that human-made materials could also be made to stiffen at will.
The biaxially stiffened concepts had higher flyaway costs than the composite-reinforced concept, even though their range capabilities were less than that of the composite concept.
The first, more accurate one, includes the "dynamics stiffening" phenomenon.
The rise of popular francophile radicalism stiffened ministerial ranks, and further strained the whigs.
Its characteristic behaviour is that when threatened it wedges itself into a crevice and stiffens its body so that predators cannot extract it.
The guide-wire was then withdrawn through the femoral vein and could be subsequently stiffened by gently applying tension to both ends.
In these circumstances the logic of accountancy was stiffened by a bureaucratic mode of reasoning, so he simply (as they say) followed orders.
For the welded, biaxially stiffened concept, the material and tooling "value-per-pound" factors were not significantly different.