Definition of "picayune"

picayune

/ˌpɪkəˈjuːn/

noun
plural picayunes
1. (especially Louisiana, historical) A small coin of the value of six-and-a-quarter cents; a Spanish coin with a value of half a real; a fippenny bit.
2. (by extension, archaic) A coin worth five cents (a nickel) or some other low value.
3. (figuratively, informal) A person regarded as unworthy of respect or useless; also, something of very little value; a trifle.
4. (figuratively, informal) An argument, fact, or other issue raised (often intentionally) that distracts from a larger issue or fails to make any difference.
adjective
comparative more picayune, superlative most picayune
1. Of little consequence; small and of little importance; petty, trivial.
  Quotations
  It's also representative of a psychological syndrome that I notice has gotten steadily worse as the Cruise wears on, a mental list of dissatisfactions and grievances that started picayune but has quickly become nearly despair-grade.
  1997, David Foster Wallace, “A Supposedly Fun Thing I’ll Never Do Again”, in A Supposedly Fun Thing I’ll Never Do Again: Essays and Arguments, Boston, Mass.: Little, Brown and Company
  [T]here are four competing groups promoting the language – and they cannot agree even on how it should be spelled (Kernewek, Kernowek, Kernuak and Curnoack, among others). It might seem like a picayune matter, akin to the rivalry in the film "Monty Python's Life of Brian" between the Judean People's Front, the Judean Popular People's Front and the People's Front of Judea. But the issue is deadly serious to speakers of Cornish.
  2005 November 17, Sarah Lyall, “In an old Celtic revival, spelling is a test of wills”, in The New York Times‎, New York, N.Y.: The New York Times Company
2. Childishly spiteful; tending to go on about unimportant things; small-minded.