Decalcify means to remove calcium from something, and its antonym is to calcify, which means to add calcium to something or to make it strong and hard by depositing calcium salts. Calcify is commonly used in medicine when referring to the formation of calcium deposits on bones or soft tissues, which can lead to diseases like osteoporosis or atherosclerosis. Another antonym for decalcify is to mineralize, which means to reinforce something with minerals, including calcium, magnesium, and phosphorus. Mineralization is crucial to maintaining healthy bones, teeth, and muscles and preventing mineral deficiencies that can lead to various health problems.