Old English sorg "grief, regret, trouble, care, pain, anxiety," from Proto-Germanic *sorg- (cf. Old Saxon sorga, Old Norse sorg, Middle Dutch sorghe, Dutch zorg, Old High German soraga, German sorge, Gothic saurga), perhaps from PIE *swergh- "to worry, be sick" (cf. Sanskrit surksati "cares for," Lithuanian sergu "to be sick," Old Church Slavonic sraga "sickness," Old Irish serg "sickness"). Not connected etymologically with sore (adj.) or sorry.