stiffens

v.使 ... 坚硬；变为浓粘；使坚定；使强硬

This lignification serves to stiffen and strengthen the cells. 木质化足以使细胞变硬和增强。

This sort of grease could not stiffen when the temprature drops. 温度下降时，这种润滑脂不会变稠。

The promise of a reward might stiffen their resolve. 答应给他们奖励可以坚定他们的决心。

He stiffened at the insult. 他听到这些侮辱的话，态度强硬起来。