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