Averse, related to the word aversion, means opposed and should be applied only to people because it is a feeling. It comes after a form of the verb to be and has the word to after it. He was averse to socializing with his ex-girlfriend. She was not averse to hard work, but it was unreasonable for her boss to expect her to work 70 hours per week.
Adverse is used to describe a noun or action. It is not a feeling but, rather, a state or condition–and an unfavorable one at that. We traveled in the 100-degree heat without any air conditioning in the car–-without a doubt, adverse conditions. A person cannot be adverse; he or she, however, can experience adversity.