TOEFL boundless Definition Without limits or constraints; infinite. Example "Her enthusiasm for space exploration is boundless." Sign in to save TOEFL PDF — $25 ← boundary bounteous → Study tips featuring "boundless" 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