Being loopy is the state of being mentally deranged, possibly out of one's
mind. Calling someone loopy is to suggest that the person is in some form of daze. Therefore their speech or acts seem incoherent and disconnected.
If one of your friends began committing
bizarre acts, such as expressing an unmistakably wrong
opinion, you would describe them as loopy.
The term loopy also doesn't need to describe a person, as inanimate objects or animals that perform seemingly peculiar acts could also be described as loopy.