Meaning of “adverse” - Learner’s Dictionary

adverse

adjective uk us /ˈædvɜːs/ formal
adverse conditions/effects/impact

things that cause problems or danger:

Pollution levels like these will certainly have an adverse effect on health.
adverse comment/publicity/reaction, etc

something negative that is said or written about someone or something

adversely adverb

(Definition of “adverse” from the Cambridge Learner’s Dictionary © Cambridge University Press)