nitpicker

[nit-pik-er] /ˈnɪtˌpɪk ər/
noun
1.
a person who nitpicks, especially habitually.
Also, nit-picker.
Origin
1950-55; nit1 + pick1 + -er1
Examples from the web for nitpicker
  • He was a nitpicker, a collector of trivial details, but was incapable of seeing a larger perspective.
  • Cool, it's my turn to be the holier than thou nitpicker.
  • When you're a journalist, you get used to being called a nitpicker--even a blood-sucking parasite.
Word Origin and History for nitpicker
n.

"pedantic critic," 1951; see nit (n.) + pick (v.).