insane
mentally ill / irrational / foolish / extreme
Adjective
This term carries a heavy shift in tone depending on the setting. In legal or clinical contexts, it describes a profound mental incapacity, though it has largely been replaced by more precise medical terminology in modern psychiatry to avoid stigma. In casual conversation, the word functions as a hyperbolic intensifier. It can describe a decision as reckless or foolish, or conversely, describe a feat as breathtakingly impressive or extreme, moving the meaning from a negative judgment to a positive expression of awe.