adverse
adj.-
1 harmful or unfavourable (adj.) C1 Advanced Formal Academicharmful, negative, or preventing success.
unfavourable or antagonistic in effect; acting against one's interests or welfare.
ExampleThe match was cancelled due to adverse weather conditions.
ExampleThe pharmaceutical company was forced to halt the clinical trial after several participants reported adverse reactions to the new medication.
UsageCommonly collocates with 'weather', 'conditions', 'effects', and 'reactions'.
Teacher's tipLearners frequently confuse this with 'averse'. Remind them that 'adverse' usually describes things or situations, while 'averse' describes a person's feelings (e.g., 'risk-averse').
PitfallThe medicine had averse side effects.The medicine had adverse side effects.Do not confuse 'adverse' (harmful conditions) with 'averse' (a person's strong dislike or opposition to something).
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2 opposite or confronting (adj.) C2 Proficiency Technical Formal Sciencefacing the opposite way or being on the opposite side.
positioned in an opposite direction or confronting; often used in technical or botanical contexts.
ExampleThe leaves grow in an adverse position along the stem.
ExampleThe researcher noted the adverse placement of the sensors, which resulted in conflicting data streams during the initial phase of the experiment.
First attested around 1374, from Old French avers (French adverse), from Latin adversus (“turned against”), past participle of advertere, from ad- (“to”) + vertere (“to turn”). See also versus.
- Adjectiveadverse
- Adverbadversely