worstworstworstsworstedworsting1adjective, adverb (bad, worse, worst)the least pleasant or suitable; the least well: He's the worst player in the team! That was the worst day of my life. Everyone played badly, but I played worst of all.oppositebestworstworstworstsworstedworsting2noun (no plural)something or somebody that is as bad as it or they can be: I'm the worst in the class at grammar.oppositebestif the worst comes to the worstif something very bad happens: If the worst comes to the worst and I fail the exam, I'll take it again next year.