The term 'LOSES RIGIDITY' can be summarized by the four-letter word 'SAGS'. This term is used to describe a situation in which something loses its stiffness or strength, becoming more flexible and less rigid. This can be seen in many materials, such as metal, wood, and plastic, when they are exposed to certain conditions, such as extreme temperatures or pressure. In some cases, this can be beneficial, as it can make the material easier to work with, but in other cases, it can be detrimental, as it can lead to structural weakness.