Adjective, also a verb. To be "
over the moon" about something. Whether you are brown-nosing a person you respect, obsessing over your crush or just being another lame fan. Even applicable to those cocky enough to be moony over themselves. The key component
is that you have to embarass yourself in some way through your
starry eyed eagerness.
"I wanted to show up at his work to
surprise him, but I thought that would be too moony"
"She was so busy mooning over her
professor she didn't even
realize class was over"