If an experience toughens you, it makes you stronger and more independent in character. They believe that participating in fights toughens boys and shows them how to be men. Toughen up means the same as toughen. He thinks boxing is good for kids, that it toughens them up My father tried to teach me to toughen up. to become tougher, or to make someone or something tougher
If you toughen something or if it toughens, you make it stronger so that it will not break easily. Do not add salt to beans when cooking as this tends to toughen the skins
If a person, institution, or law toughens its policies, regulations, or punishments, it makes them firmer or stricter. Talks are under way to toughen trade restrictions Toughen up means the same as toughen. The new law toughens up penalties for those that misuse guns