adverse adj. 1. antagonistic or actively hostile 2. unfavourable or detrimental.
averse adj. 1. opposed to or disinclined 2. feeling of repugnance.
Words in the Wild: I’m averse to taking prescription drugs because, with my allergies, they often have adverse reactions.
I’ve often find that writers use the word adverse when averse is called for.
You may have noticed that averse looks a lot like the root of the word aversion, and that’s because they are related: both words refer to a strong dislike, repugnance or loathing. Knowing this connection can help you decide whether averse is the word you need.
Still vexed? You can find a complete list of the Word Blog’s lexical vexations here.