TOEFL IELTS harmful Definition Causing or likely to cause damage or injury. Example "Smoking is harmful to your health and can lead to lung disease." Sign in to save TOEFL Quiz → IELTS Quiz → ← hardy harmless → Study tips featuring "harmful" Map Each Word Into a Connected Network Audit Your Own Writing for Lexical Resource Track How TOEFL Words Behave With Others 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