Synonyms for Reversion (same or very similar meaning)
WordNet sense 1 (a reappearance of an earlier characteristic):
atavism, throwbackWordNet sense 2 (turning in the opposite direction):
reversal, reverse, turnabout, turnaroundWordNet sense 3 (returning to a former state):
regress, regression, retrogression, retroversion, regressWordNet sense 4 (a failure to maintain a higher state):
lapse, relapse, backsliding, lapsing, relapsing, reverting, relapseFrom the ODE community, based on WordNetadd/edit