Persnickety is picky and cranky combined.

1. • Overparticular about trivial details; fastidious.
   • Snobbish; pretentious.
2. Requiring strict attention to detail; demanding: a persnickety job.

1. Used colloquially of one who is overly conceited or arrogant; "a snotty little scion of a degenerate family"-Laurent Le Sage; "they're snobs--stuck-up and uppity and persnickety"
2. Characterized by excessive precision and attention to trivial details; "a persnickety job"; "a persnickety school teacher"

Synonyms (from the Microsoft Word Thesaurus) include: pernickety (notice the lack of "s"), fussy, picky, fastidious, prickly, difficult to please, particular, hard to please, choosy, funny, finicky. Strange that they omit "uppity" and "snobbish."

Etymology: a variation coined circa ~1905 of "pernickety", which was coined circa ~1808 (some sources say 1818), which is probably a variation of the Scottish "pernicky" (some sites in a google search claim this, others claim "origin unknown.") It stops there -- the assumption is that it has something to do with "particular," perhaps a dialectical transformation, an exaggerated mockery of the original word "particular."

The great thing about this word is that it's an onomatopoeia of sorts (but a pedant would be correct in saying it's not technically such); the mere sounds that comprise the word "persnickety" immediately give one an impression of haughtiness and pickiness. "Cranky" isn't quite a synonym, but it would be persnickety of me to insist that it not be considered as such. Neither is "pedantic." "Cranky" merely implies having a negative disposition, or being easily annoyed. "Persnickety" implies arrogance and fastidiousness -- it's close, but not quite. "Pedantic" doesn't quite cut it either -- whereas "persnickety" implies excessive attention to detail, "pedantic" implies ostentatious adherence to "the book." Also similar, but not quite a synonym by most (any?) thesaurus's standards.

A persnickety person might be annoyed by my use of "apostrophe + s" in the last sentence as in "thesaurus's." An informed pedantic person would know that this is technically correct usage, but either form (apostrophe or apostrophe + s) is acceptable (I just found this out myself awhile back whilst being persnickety over this usage on The Filthy Critic's website) because while "thesaurus" does end in an "s," it's not a plural word, and thus "apostrophe + s" is perfectly acceptable (do some searches on the Internet if you'd like; Random House supports this convention). I personally loathe this usage and was merely making an example; in my experience I've noticed that most professional print and web editors stick to the "all words ending with s get an apostrophe tacked on in their possessive form" rule.

Exercise: Try as hard as you can to find a valid excuse to call somebody "persnickety" today. If you work in the corporate world, it shouldn't take long.