Tomfoolery gett:

foolish or silly behaviour.

synonymer: silliness, fooling, clowning, capering, capers, antics, pranks, tricks, buffoonery, skylarking, nonsense, horseplay, mischief, foolishness, foolery, stupidity; informalmessing about/around, larking about/around, larks, shenanigans; informalmonkey tricks

Now: commit tomfoolery