Restiffnes or Restiffness: How To spell?
The word Restiffnes is misspelled against Restiffness, a noun meaning "Restiveness."
Restiffness has double 'ss' in the end mispronounced as 's'Remember double 'SS' appears in the end of this word which should not be misspelled with single 'S'
Wrong Spelling:  restiffne-s  Correct Spelling:  restiffne-ss 
Find more wrongly spelled words of Restiffness to spell it well.