a) Fastidious or fussy.
Marjorie glanced up and down the long street. “Well, I never in my life saw so many different kinds of houses!” she exclaimed. “Aren’t they funny! Why, they look almost like people. Look at that little persnickety one over there — the white, white one with the green, green blinds — doesn’t it look exactly like —”
b) Obsessive about mundane details, demanding for precision.
I have just read the article in your issue for May 16 on dialectic English. The word tempest recalls the surprise I felt at the beginning of three years residence on Cape Cod to hear the word used commonly as an exact synonym for thunderstorm.
Wikipedia foundation.