stiffen

transitive & intransitive verb

To make or become stiff or stiffer.

To become stiff.

To become less soft or fluid; grow thicker or harder; become inspissated: as, jellies stiffen as they cool.

To become steady and strong: as. a stiffening breeze.

To become unyielding; grow rigid, obstinate, or formal.

To become higher in price; become firmer or more unyielding: as, the market stiffens.

To make stiff.

To make rigid, constrained, formal, or habitual.

To make more thick or viscous; inspissate: as, to stiffen paste.

To make stubborn or obstinate.