The second definition ironically makes the common mistake discussed below it in Usage notes. From Merriam Webster's 2009 dictionary entry: Adverse is seldom used of people but rather of effects or events, and it usually conveys a sense of hostility or harmfulness: adverse reviews; adverse winds; adverse trends in the economy. Related nouns are adversity and adversary: Adversities breed bitterness. His adversaries countered his every move. Averse is used of persons and means “feeling opposed or disinclined”; it often occurs idiomatically with a preceding negative to convey the opposite meaning “willing or agreeable,” and is not interchangeable with adverse in these contexts: We are not averse to holding another meeting.
And so the example of usage for the second def. I'm not adverse to continuing the debate. Is improper. I'm going to change it from the above to: opposing one's interests or desire: adverse circumstances.