"That most noble imp, the prince's grace, your most dear son."
The special sense of "young devil" appears to be due to the frequent occurrence of such phrases as "imps (children) of Satan," "the devil and his imps," etc. Ger. impfen also means to vaccinate. Our earlier term inoculate[88] originally meant to graft, and, in fact, engraft was also used in this sense.
Zest is quite obsolete in its original meaning of a piece of orange peel used to give piquancy to wine. It is a French word of unknown origin, properly applied to the inner skin of fruit and nuts. Cotgrave explains it as "the thick skinne, or filme whereby the kernell of a wallnut is divided."
FOOTNOTES:
[81] It would be interesting to trace the rise and spread of nautical metaphor in English. We have a good example of the transition from the bucolic to the nautical in the expression "To lose the ship for a ha'porth of tar." Few people who use this metaphor know that ship is here the dialect pronunciation of sheep; cf. Ship Street, at Oxford (and elsewhere), for Sheep Street. Tar was, and is, used as a medicine for sheep, but in this particular case the allusion seems to be rather to the marking of sheep with tar; cf. "tarred with the same brush," i.e., members of the same flock.
[83] Lat. fustis, a staff, cudgel, gave also Old Fr. fust, a kind of boat, whence obsolete Eng. foist in the same sense. Both meanings seem to go back to a time when casks and boats were "dug out" instead of being built up.
[84] Related are bouche béante, or bée, mouth agape; bâiller, to yawn; and badaud, "a gaping hoydon" (Cotgrave, badault).
[85] Cf. the Stickit Minister.
[86] Or perhaps *alboculare, as albus oculus, lit. white eye, is used of blindness in an early Vulgar Latin glossary.