Susteynment or Sustainment: How To spell?
The word Susteynment is misspelled against Sustainment, a noun meaning "The act of sustaining; maintenance; support."
Word contains consecutive vowels 'AI' in between alphabets sust & nment is misspelled as 'EY'Wrong Spelling:  sust-ey-nment  Correct Spelling:  sust-ai-nment 
Check more misspelled words of Sustainment to spell it correct.