1.
If you say that someone is ~, you mean that they cannot think clearly any more, especially because they are old. (INFORMAL)
If you don’t keep your brain working you go ~.
= dotty
ADJ: v-link ADJ
2.
If someone goes ~ over a person or thing, they like them very much. (INFORMAL)
My daughter is just ~ over men with hairy chests.
= crazy
ADJ: v-link ADJ