Sexenial or Sexennial: How To spell?
The word Sexenial is misspelled against Sexennial, a noun meaning "A sexennial event."
Sexennial has double "nn" is mispronounced as "n"Remember double 'NN' in between the strings sexe & ial which should not be misspelled with single 'N'
Wrong Spelling:  sexe-n-ial  Correct Spelling:  sexe-nn-ial 
Find more wrongly spelled words of Sexennial to spell it well.