Hisingly or Hissingly: How To spell?
The word Hisingly is misspelled against Hissingly, an adverb meaning "With a hissing sound."
Hissingly has double "ss" is mispronounced as "s"Remember double 'SS' in between the strings hi & ingly which should not be misspelled with single 'S'
Wrong Spelling:  hi-s-ingly  Correct Spelling:  hi-ss-ingly 
Find more wrongly spelled words of Hissingly to spell it well.