The word Sustuner is misspelled against Sustainer, a noun meaning "One who, or that which, sustains."
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Word contains consecutive vowels 'AI' in between alphabets sust & ner is misspelled as 'U'
Wrong Spelling:  sust-u-ner 
Correct Spelling:  sust-ai-ner 
Check more misspelled words of Sustainer to spell it correct.