A more thorough explanation:

Term: aemulationis causa
Definition: A Latin term used in history to describe actions taken for the purpose of competing with or irritating someone.
Examples: A king might declare war on a neighboring kingdom aemulationis causa, meaning that he is doing it to show that his kingdom is stronger or to annoy the other king. In modern times, someone might start a social media feud with a rival aemulationis causa, trying to get more followers or attention.
Explanation: The term aemulationis causa is used to describe actions that are taken not for a practical reason, but for the purpose of competing with or annoying someone. The examples show how this term can be used in different contexts, from historical wars to modern social media feuds. In both cases, the actions taken are not necessary or practical, but are done to show superiority or to irritate someone.