SAT TOEFL IELTS invaluable Definition Extremely useful; too valuable to be measured. Example "Her advice was invaluable during the crisis." Sign in to save SAT Quiz → TOEFL Quiz → IELTS Quiz → ← invalidate invariably → Study tips featuring "invaluable" Spot the Vocabulary Trap in Every Question Audit Your Own Writing to Find Gaps TOEFL Academic Vocabulary: Study by Topic Related words SAT abase SAT abdicate SAT abdomen SAT abduction SAT abet SAT abeyance SAT abject SAT abjure SAT ablution SAT abnegate SAT abnormal SAT abominable