‘Adverse’ and ‘averse’ are not only spelled similarly (with the ‘d’ in ‘adverse’ being the only difference), they are also both adjectives with negative connotations, and hence easily confused.
‘Adverse’ means ‘unfavourable’, or ‘harmful’. Therefore, if a sportsman is said to perform well in adverse conditions, it means that he or she performs well in conditions that are not easy to play in. It is used in reference to things, actions or events, rather than people.
‘Averse’ describes a strong disinclination. It is used of things and people, but we never speak of an averse thing or person. It is most often used in the form averse to, as in I am averse to speaking in public.