contrary to your interests or welfare
"adverse circumstances"
"made a place for themselves under the most untoward conditions"
Unfavorable; antagonistic in purpose or effect; hostile; actively opposing one's interests or wishes; contrary to one's welfare; acting against; working in an opposing direction.
"The sudden adverse wind caught us off guard and pushed our sailboat directly back toward the rocky shore, threatening to capsize it."
In plain English: Adverse means harmful, unfavorable, or causing trouble.
"The adverse weather conditions forced the flight to be delayed."
Usage: Use "adverse" to describe conditions, effects, or circumstances that are harmful or unfavorable to your specific goals, such as adverse weather delaying a flight. Do not use it to mean simply bad or negative, as it specifically implies something acting against your interests.
The word "adverse" entered English around 1374 via Old French and originally meant "turned against." This sense comes from the Latin root for turning toward something, which evolved to describe opposition or hostility.