What is Worst?
Worst is (adj) worse than anything else This summer is the worst for fifty years. I think this is the worst film he’s ever made. Antonym best (adv) less well than anything or anyone else or than at any other time It’s difficult to say which team played worst. She works worst when she’s tired. (noun) a very bad thing The worst of the bad weather is past now. to prepare for the worst to get ready to have bad news Your father was very badly injured – you must prepare for the worst.
source: Easier English, Student Dictionary Upper Intermediate Level