A negative effect or impact on something.
1. The study found that there was a significant adverse impact on the environment due to the increase in industrial activity. 2. The company's decision to lay off a large number of employees had an adverse impact on the local economy.
1. "There is no question that there is an adverse impact on the planet by the use of fossil fuels." Leonardo DiCaprio, Interview with National Geographic 2. "The adverse impact of climate change is no longer a conjecture of the future, it is happening now." Ban Ki