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.