E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A graft; whence also a child; as, You little imp. In hawking, to
imp a feather is to engraft or add a new feather for a broken
one. The needles employed for the purpose were called imping
needles. Lord Cromwell, writing to Henry VIII., speaks of that
noble imp your son. Let us pray for the kings most excellent
majesty and for his beloved son Edward, our prince, that most
angelic imp.Pathway to Prayer.