Adverse - averse

Don't confuse these two words. If you do, spellcheckers will let you get away with it. Their meanings are not very far apart, but should not be confused.

• adverse means, roughly, 'contrary', 'against' or 'unfavourable'. If you have adverse wind, it is blowing in your face; adverse fortune is bad luck; and adverse effects are those you don't want. Adverse is an adjective used to describe external things like weather or chance or results.
• averse on the other hand is used to describe an internal state of mind. "I am averse to your going," says the jealous father; "The politician found himself averse to telling the truth about his relationship in public." It means 'opposed [to]', 'disinclined', 'disliking', 'against'. It is often found in the construction (a litotes) "I am not averse to [e.g. another drink]."

You may also like to see AWE's advice on adversary.