to go backward into an earlier and usually worse condition: to retrogress to infantilism.
2.
to move backward.
Origin: 1810–20; < L retrōgressus ptp. of retrōgradī to go back or backward, equiv. to retrō-retro-+ gred-, comb. form of gradī to step, go (see grade) + -tus ptp. suffix, with dt > ss