Old English grædig (West Saxon), gredig (Anglian) "voracious, hungry," also "covetous, eager to obtain," from Proto-Germanic *grædagaz (source also of Old Saxon gradag "greedy," Old Norse graðr "greed, hunger," Danish graadig, Dutch gretig, Old High German gratag "greedy," Gothic gredags "hungry"), from *græduz (source also of Gothic gredus "hunger," Old English grædum "eagerly"), possibly from PIE root *gher- (2) "to like, want" (source of Sanskrit grdh "to be greedy").
In Greek, the word was philargyros, literally "money-loving." A German word for it is habsüchtig, from haben "to have" + sucht "sickness, disease," with sense tending toward "passion for."