September is Etymology Month (28)

forget O.E. forgietan, from for-, used here with negative force, "away, amiss, opposite" + gietan "to grasp". To "un-get," hence "to lose" from the mind. A common Germanic construction (cf. O.S. fargetan, O.Fris. forjeta, Du. vergeten, O.H.G. firgezzan, Ger. vergessen "to forget"). The literal sense would be "to lose (one's) grip on," but that is not recorded in any Germanic language.