Source : Webster's Revised Unabridged Dictionary (1913)

Perfectionist \Per*fec"tion*ist\, n.
   One pretending to perfection; esp., one pretending to moral
   perfection; one who believes that persons may and do attain
   to moral perfection and sinlessness in this life. --South.

Source : WordNet®

perfectionist
     n : a person is displeased by anything that does not meet very
         high standards