[noun] [U] [dated] - foolish, often playful, behaviourThat's enough tomfoolery, class - now let's get on with some work, shall we!Sergeant Lander described the incident involving two eight-year-old boys as "a piece of tomfoolery that went horribly wrong."
TOMFOOLERY
Meaning of TOMFOOLERY in English
Cambridge English vocab. Кембриджский английский словарь. 2012