Averse means (1) to be opposed or (2) to be strongly disinclined. Adverse means to be acting in opposition. Averse describes an attitude or a feeling, while adverse describes something that works against something else. The two adjectives are often confused.
Synonyms and examples
Averse—some of whose synonyms are opposed, reluctant, hostile, and disinclined—is most commonly used in reference to a person or a group of people—for example:
The yen jumped in Asian trade as investors became more averse to risk . [Reuters]
If you’re averse to spoilers, close your browser window right now. [Latino Review]
Averse is often used in the phrasal adjective risk-averse—frequently in financial contexts.
Adverse—some of whose synonyms are harmful, negative, unfavorable, and detrimental—usually refers to things, conditions, or actions—for example:
The panel concluded that sounds or vibrations emitted from wind turbines have no adverse effect on human health. [Simcoe Reformer]
But a study finds that having some adverse experiences in the past may make you mentally tougher. [Los Angeles Times]