nitpicker

English Thesaurus

1. someone who makes small and unjustified criticisms (noun.person)

hypernym	:	critic,
definition	:	someone who frequently finds fault or makes harsh and unfair judgments (noun.person)

derivation	:	nitpick,
definition	:	be overly critical; criticize minor details (verb.communication)

derivation	:	nitpick,
definition	:	be overly critical; criticize minor details (verb.communication)