Efficacy
mediumNeutral toneEF-ih-kuh-see
noun
Definition
the power to produce a desired effect or result; effectiveness
Memory hook
EFFICacy: it's about whether something is 'EFFICient at making' (fac = make) the result you want.
Word roots
Learning roots unlocks whole word families. Study common GRE root words.
Examples
“Clinical trials questioned the efficacy of the new vaccine in older patients.”
“The efficacy of the policy will only become clear over several years.”
Test yourself
Fill in the blank with the right word:
“Clinical trials questioned the ______ of the new vaccine in older patients.”
Show answer
efficacy
Synonyms
Antonyms
Categories
GRE Tip
Efficacy is a medium-difficulty GRE word. On the GRE, you might see it paired with synonyms like "effectiveness" or "potency" in Sentence Equivalence questions. Look for contrast clues (however, despite, although) that signal the opposite meaning. Words like "ineffectiveness".
Related GRE Words
adulterate
To make something poorer in quality by adding another substance
deterrent
something that discourages or prevents an action
homogeneous
of the same kind; uniform throughout
inconsequential
of little importance; trivial
insipid
Lacking flavor, zest, or interest; dull and unengaging
meticulous
Showing great attention to detail; very careful and precise
Master efficacy and 1,000+ GRE words
Learn through stories, practice with real GRE questions, and never forget with spaced repetition.