bonkers
adj. B2 Upper Intermediate US //ˈbɑŋkɝz// UK //bˈɒŋkəz// bonkers
adj. completely crazy, silly, or wild. You use this when something or someone is acting in a very strange or funny way.
adj. mentally unbalanced or extremely foolish; characterized by wild or eccentric behavior. Often used predicatively after linking verbs like 'go' or 'be'.
The crowd went bonkers when the band finally started playing.
The traffic in the city center during the holiday season is absolutely bonkers.
While the initial proposal seemed slightly eccentric, the final version of the plan was completely bonkers and lacked any logical foundation.
Unknown. Perhaps from bonk (a blow or punch on the head), perhaps related to earlier bonce.
Usage
Informal in register; frequently follows the verb 'go' to describe a sudden change in behavior.