A boomer is a person born in the years 1946-1954 and is commonly made fun of because of their stereotypical clumsiness and dad-jokes.
"Why didn't the toilet paper cross the road? Because it got stuck in a crack!" Said the boomer, while his daughter gave him the face of disapproval and his grandson started laughing along.
A foolish or annoying person.
"Could you two nincompoops cut it out!?" Said the mother to her two sons arguing.