Stiff″en (?), v. t. [imp. & p. p.Stiffened (?); p. pr. & vb. n.Stiffening.] [See Stiff.] 1. To make stiff; to make less pliant or flexible; as, to stiffen cloth with starch.
Stiffen the sinews, summon up the blood. Shak.
2. To inspissate; to make more thick or viscous; as, to stiffen paste.
3. To make torpid; to benumb.