If you act natural it’s not natural
An original COPY isn’t original because it’s a copy of the original
Seriously funny is saying something is seriously funny yet funny is an antonym of serious
Clearly confused is saying that confusion is clear; yet they are both antonyms of each other
Jumbo shrimp is an oxymoron because shrimp are rather small yet they are called jumbo which would usually mean grand or large, but it is saying that the shrimp is large compared to an average sized shrimp. Hope this helps