gaga  
adjective  informal uk/ˈɡɑː.ɡɑː/ us/ˈɡɑː.ɡɑː/
  (MENTALLY UNCLEAR)      
  老糊涂的;老朽的;迷糊的
unable to think clearly and make decisions because of old age
  My granny's 94 and she's a bit gaga. 我奶奶94了,有点糊涂了。 
 I know I'm 73 but I haven't gone gaga yet! 我知道我73了,可是我还没老糊涂! 
 Compare: senile
   (IN LOVE)      
 [ after verb ]狂热的;着迷的 
having a strong but usually temporary love for someone
  She's totally gaga about/over him! 她完全被他给迷住了! 
 Just standing near her makes him go gaga! 在她身边站一站他就会神魂颠倒!