Old English forgietan "lose the power of recalling to the mind; fail to remember; neglect inadvertently," from for-, used here probably with privative force, "away, amiss, opposite" + gietan "to grasp" (see get). To "un-get," hence "to lose" from the mind. A common Germanic construction (compare Old Saxon fargetan, Old Frisian forjeta, Dutch vergeten, Old High German firgezzan, German vergessen "to forget"). The physical sense would be "to lose (one's) grip on," but that is not recorded in any historical Germanic language. Figurative sense of "lose care for" is from late 13c. Related: Forgetting; forgot; forgotten.