Progresionist or Progressionist: How To spell?
The word Progresionist is misspelled against Progressionist, a noun meaning "One who holds to a belief in the progression of society toward perfection."
Progressionist has double "ss" is mispronounced as "s"Remember double 'SS' in between the strings progre & ionist which should not be misspelled with single 'S'
Wrong Spelling:  progre-s-ionist  Correct Spelling:  progre-ss-ionist 
Find more incorrect spellings of Progressionist to spell right way.