Since instaurations means the act of introducing or initiating something new, its antonyms would be words that imply a lack of change or progression. Some potential antonyms for instaurations include "retrogression," "regression," "reversion," "decline," and "inactivity." These words all suggest a return to previous states, rather than a movement towards something new. Alternatively, "stagnation," "stasis," and "inertia" also convey a lack of motion or change, but without necessarily implying a reversal of progress. Overall, these antonyms for instaurations communicate a sense of complacency and resistance to advancement or improvement.