1. very tired; exhausted: "I'm knackered by the end of the day"Similarexhaustedtired outworn outwearydog-tiredbone-tiredbone-wearyready to dropon one's last legsasleep on one's feetdrainedfatiguedenervateddebilitatedspentjet-laggedout of breathbreathlesspantingpuffingpuffedpuffed outpuffing and blowinggasping (for breath)informal:done inall indead on one's feetbeatdead beatshatteredbushedfagged outknocked outwiped outrunning on emptyzonked outworn to a frazzlefrazzledbushwhackedwhacked (out)shagged outjiggeredwabbitpoopedtuckered outfriedwhippedgassedstonkeredvulgar slang:buggeredrootedarchaic:toilwornrare:fordoneOppositefresh as a daisyraring to go
2. severely damaged or broken:"he had seen Sonny flying around on a knackered old bike for the last two weeks"Similarbrokendamagedfaultydefectiveunsoundnot workingnot functioningnonfunctioningmalfunctioningin disrepairinoperativeout of order/commissionnot in working orderbroken-downout of kilterdowninformal:on the blinkon its last legskaputbustbustedconked outacting/playing upgone haywiregone phutfinisheddone forwonkydudduffvulgar slang:buggeredOppositeworkingfixed
