TOEFL strengthen Definition To make or become stronger in power, quality, or degree. Example "Daily exercise can strengthen your immune system." Sign in to save TOEFL PDF — $25 ← streak strenuous → Study tips featuring "strengthen" TOEFL Academic Vocabulary: Study by Topic Related words TOEFL brighten GRE abash GRE abate GRE abbreviate GRE abbreviation SAT abdicate GRE abduct SAT abet GRE abhor GRE abide SAT abject TOEFL ablaze