This ubiquitous term, often used pejoratively, can mean:
- mentally ill
- psychotic
- insane
- hysterical
- nonsensical
- irrational
- self-defeating
- uninhibited
- passionate
- wild
crazy
(balmy, barmy, batty, bonkers, bughouse, cra cra, cra-cra, cracked, crackers, cuckoo, daft, loco, loony, mad, nuts, nutso, off the rocker, wacko, wacky)