adj. Chiefly British
Very tired; exhausted
Knackered (from the verb ‘Knacker’) has three meanings. The most common usage of ‘knackered’ is worn out, tired or exhausted (eg: “I missed the last train and had to walk home and now I’m absolutely knackered”)
It can also mean broken (eg “Can I come round and watch your telly as ours is knackered?”) or thwarted (prevented from succeeding at a task) (eg: “My car broke down so our holiday plans were knackered”).
The verb knacker can also mean to ruin something (eg “Keep fiddling with the light switch and you’ll knacker it”).
You can also use the adjective knackering in the place of tiring or exhausting (eg “Running for that train is the most knackering thing I’ve ever done”).
And to round things off, we finish with a little Cockney Rhyming Slang … cream crackered is rhyming slang for knackered !