1. no longer in possession of all one's mental faculties, especially on account of old age: informal"I want to write my memoirs before I go too gaga"
▪ very enthusiastic and excited about someone or something:informal"moviegoers went gaga over Harry Potter"
Word Originearly 20th century: from French, ‘senile, a senile person’, reduplication based on gâteux, variant of gâteur, hospital slang in the sense ‘bed-wetter’.
