retarded

adj backward in physical or (esp) mental development 身体或（尤指）精神发育迟缓的; 智力迟钝的: be severely (mentally) retarded （智力）发育极为迟缓.

resurge, resurgence, resurgent, resurrect, resurrection, resuscitate, resuscitation, ret (also retd), retail, retailer, retain, retainer, retaining wall, retake, retaliate, retaliation, retaliatory, retard, retardant, retardation, retch, retd, retell, retention, retentive, retentively, retentiveness, rethink, reticence, reticent, reticently, reticulated, reticulation, reticule, retina, retinue, retire, retired, retirement, retirement age,