Indefysible or Indefeisible: How To spell?

The word Indefysible is misspelled against Indefeisible, an adjective meaning "Indefeasible."

Word contains consecutive vowels 'EI' in between alphabets indef & sible is misspelled as 'Y'
Wrong Spelling:  indef-y-sible 
Correct Spelling:  indef-ei-sible 
Find more wrongly spelled words of Indefeisible to spell it well.