I . n.
1.
Regression, regress, retrocession, retrogression, reflux, refluence, return.
2.
Decline, decay, deterioration, degeneration, degeneracy, caducity, wane, waning.
3.
Decrease, diminution, abatement, decrement, subsidence.
II . v. n.
1.
Recede, retire, flow back.
2.
Decline, decrease, decay, wane, sink, fall away.