Stuner or Stunner: How To spell?
The word Stuner is misspelled against Stunner, a noun meaning "One who, or that which, stuns."
Stunner has double "nn" is mispronounced as "n"Remember double 'NN' in between the strings stu & er which should not be misspelled with single 'N'
Wrong Spelling:  stu-n-er  Correct Spelling:  stu-nn-er 
Check more misspelled words of Stunner to spell it correct.