Involutional refers to a process of degeneration or decline, often occurring in relation to the aging process. Synonyms for involutional might include "atrophic," "senescent," or "withering." These words suggest a similar process of deterioration, often related to an increasing level of age or decreased function. Other synonyms for involutional might include "declining," "degenerative," "diminishing," or "weakening." All of these words suggest a gradual decrease in vitality or function, often associated with a decline in physical or mental health. Ultimately, the choice of synonyms for involutional will depend on the context in which the word is being used and the specific meaning that the writer or speaker wishes to convey.