1911 Encyclopædia Britannica/Imp
IMP (O. Eng. impa, a graft, shoot; the verb impian is cognate with Ger. impfen, to graft, inoculate, and the Fr. enter; the ultimate origin is probably the Gr. ἐμφύειν, to implant, cf. ἔμφυτος, engrafted), originally a slip or shoot of a plant or tree used for grafting. This use is seen in Chaucer (Prologue to the Monk’s Tale, 68) “Of fieble trees ther comen wrecched ympes.” The verb “to imp” in the sense of “to graft” was especially used of the grafting of feathers on to the wing of a falcon or hawk to replace broken or damaged plumage, and is frequently used metaphorically. Like “scion,” “imp” was till the 17th century used of a member of a family, especially of high rank, hence often used as equivalent to “child.” The New English Dictionary quotes an epitaph (1584) in the Beauchamp chapel at Warwick, “Heere resteth the body of the noble Impe Robert of Dudley . . . sonne of Robert Erle of Leycester.” The current use of the word for a small devil or mischievous sprite is due to the expressions “imp of Satan, or of the devil or of hell,” in the sense of “child of evil.” It was thus particularly applied to the demons supposed to be the “familiar” spirits of witches.