In slang, the term “cougar” typically refers to an older woman who is attracted to or dates significantly younger men. The opposite of a “cougar” in this context would be a term used to describe an older man who is attracted to or dates significantly younger women.
A commonly used term for this in slang is a “silver fox.” A “silver fox” refers to an older man, often with gray or silver hair, who is seen as attractive or appealing, particularly to younger women.
So, the opposite of a “cougar” would be a “silver fox” in this specific slang context.