be knackered

1. To be very tired or fatigued; to be exhausted. I was so knackered after that hike that I went right to bed after we got home. A: "The kids were up all night again. I haven't gotten a proper night's sleep all week!" B: "You must be knackered." Rover's spent most of the day snoozing in his dog bed—guess he's still knackered from that hike I took him on yesterday!

2. To not be functioning or operating properly at all; to be completely out of order. It sounds like your fridge is knackered, mate. You're probably better off just getting it replaced than trying to repair it. A: "Hey, why isn't the CD playing?" B: "Sorry, the disc drive in the stereo is knackered." Well, I was going to make a smoothie, but the blender's knackered, it seems.