Desipience is a noun that refers to silliness. 

The Latin word sapere (suh PAIR ay) means ‘to be wise.’ By adding the prefix D-E for ‘away from,’ we get a word for behavior that is far away from being wise. Here’s an example:

It’s embarrassing to consider how much of my youth I wasted on various forms of despience. Being a full-time goof may be more fun than being productive and industrious, but I can say from personal experience, it doesn’t pay very well.