Crossword clues for the word: EFFICACY The word EFFICACY has appeared as an answer to at least 5 crossword clues on different crossword puzzles. Crossword clues for EFFICACY Showing 1 to 5 of 5 results Clue(s) Ability to work Effectiveness Force Jeff, not Jack, to overcome cold collecting Bill Impression, not good, full of mostly rubbish ability to produce desired results Productiveness