Eficacy or Efficacy: How To spell?
The word Eficacy is misspelled against Efficacy, meaning "production of a desired result"
Efficacy has double "ff" is mispronounced as "f"Remember double 'FF' in between the strings E & icacy which should not be misspelled with single 'F'
Wrong Spelling:  E-f-icacy  Correct Spelling:  E-ff-icacy 
Find more wrongly spelled words of Efficacy to spell it well.