Manerism or Mannerism: How To spell?
The word Manerism is misspelled against Mannerism, a noun meaning "Adherence to a peculiar style or manner; a characteristic mode of action, bearing, or treatment, carried to excess, especially in literature or art."
Mannerism has double "nn" is mispronounced as "n"Remember double 'NN' in between the strings ma & erism which should not be misspelled with single 'N'
Wrong Spelling:  ma-n-erism  Correct Spelling:  ma-nn-erism 
Find more wrongly spelled words of Mannerism to spell it well.