Add this one to your list of words that are more useful than they look. A nannikin is a time-consuming task that requires a great deal of care and attention. Y’know, literally the worst kind of job.
That’s a word from the English Dialect Dictionary, which defines a nannikin-job as “a piece of work requiring neatness and delicacy.”
Etymologically, it probably comes from nannick, another old local English word that, as a noun, is used in a variety of senses to refer to something throwaway or foolhardy (“a childish fancy,” “a foolish person,” “a knickknack”), and as a verb can variously be used to mean “to play the fool,” “to dawdle when you should be working,” and (perhaps as a consequence) “to change employment frequently.” It can also be used to mean “to do light, irregular work”—and it’s perhaps from there that a later sense of a time-consuming task eventually developed.