Ineficacy or Inefficacy: How To spell?
The word Ineficacy is misspelled against Inefficacy, a noun meaning "Want of power to produce the desired or proper effect; inefficiency; ineffectualness; futility; uselessness; fruitlessness; as, the inefficacy of medicines or means."
Inefficacy has double "ff" is mispronounced as "f"Remember double 'FF' in between the strings Ine & icacy which should not be misspelled with single 'F'
Wrong Spelling:  Ine-f-icacy  Correct Spelling:  Ine-ff-icacy 
Find more wrongly spelled words of Inefficacy to spell it well.