toughening
nounUK /ˈtʌfənɪŋ/
US /ˈtʌfənɪŋ/
The act of making something stronger or harder to break.
The toughening of the glass made the windows safer.
OTHER MEANINGS
2. The process of becoming more strict or severe.
The toughening of the rules surprised the players.
3. The act of making a person more able to handle difficulty.
Training camp was a toughening experience for the young athletes.
4. A change that makes a material more resistant to damage.
The toughening of the metal helped it last longer.