Noun

• S: (n) regress, reasoning backward (the reasoning involved when you assume the conclusion is true and reason backward to the evidence)
• S: (n) regression, regress, reversion, retrogression, retroversion (returning to a former state)

Verb

• S: (v) regress (go back to a statistical means)
• S: (v) revert, return, retrovert, regress, turn back (go back to a previous state) "We reverted to the old rules"
• S: (v) regress, retrograde, retrogress (get worse or fall back to a previous condition)
• S: (v) relapse, lapse, recidivate, regress, retrogress, fall back (go back to bad behavior) "Those who recidivate are often minor criminals"