The word "become tender" refers to something that becomes soft, delicate, or gentle. Its antonyms can be "harden," "toughen," or "coarsen." When something hardens, it becomes rigid, solid, and unyielding. Toughening means the process of making something stronger, durable, and resilient. Meanwhile, coarsening implies the opposite of becoming tender. It means to make something rough, crude, or vulgar. These antonyms can be used in different contexts, such as cooking, skincare, or emotional responses. For example, one might harden their heart to protect themselves from pain, toughen their skin to prevent injury, or coarsen their language when expressing anger.