The word Undefeysible is misspelled against Undefeasible, an adjective meaning "Indefeasible."
-->
Undefeasible has vowels 'ea' together mispronounced as 'ey'
Word contains consecutive vowels 'EA' in between alphabets undef & sible is misspelled as 'EY'
Wrong Spelling:  undef-ey-sible 
Correct Spelling:  undef-ea-sible 
Find more wrongly spelled words of Undefeasible to spell it well.