stiffened
verb (past tense)UK /ˈstɪfənd/
US /ˈstɪfənd/
Became hard or firm and stopped bending easily.
The wet cloth stiffened when it dried in the sun.
OTHER MEANINGS
2. Became more formal or less relaxed in manner.
Her voice stiffened when she spoke to the stranger.
3. Made stronger or more determined.
The team's resolve stiffened after the early setback.
4. Became painful and hard to move, as a muscle or joint.
His neck stiffened after sleeping in an odd position.