Top definition
Man old enough to be a Grandpa, that has a new baby of his own.
Daryl is a Grandpa Daddy, he and his younger wife is having a baby.
by mimmMMIKEOWR MIKE August 25, 2018
Get the Grandpa Daddy neck gaiter and mug.
Aug 11 Word of the Day
A phrase to describe someone who is cognitively degenerating. Synonym of "going off the deep end". Can have varying degrees of severity.

Reference to the song "Hey You" by Pink Floyd. The line "and the worms ate into his brain" makes no sense in an otherwise linear and literal narration throughout the lyrics.
"My boyfriend has a total case of brain worms. He told me the cat was bugged so the Feds could listen in on us having sex..."

or

"You totally stumbled over that entire sentence. Can't speak English all of a sudden? What, do you have brain worms?"
by _Jez_ October 03, 2009
Get the brain worms neck gaiter and mug.
2
the salutation used by a child that is the result of father/daughter incestual sex.
woman; "you'd better not let grandpa daddy know we've been having sex!"

tween; "ok mommy, but grandpa daddy told me the same thing too!"
by Paul J Parkinson March 24, 2005
Get a grandpa daddy mug for your cousin James.