Water softening is the process of removing hard minerals from water like calcium and magnesium. If you're looking for synonyms for water softening, they could include terms like demineralization, ion exchange, or mineral removal. Another common term for water softening is descaling, which refers to the removal of mineral scale buildup in water treatment equipment. Other synonyms for water softening might include filtration, purification, conditioning, or treatment. Ultimately, the choice of which synonym to use might depend on the specific context in which you are discussing the process of removing hard minerals from water and the intended audience of your communication.