1. to get wasted
2. to give up
3. to be in a constant sullen mood
4. to be too lazy to do anything
5. a word used to express surprise (usually a negative one)
This phrase is usually used in the past tense (i.e., keished out).
2 - "Everyone keished out on that question in the Biology exam."
3 - Guy A:"Why do you look so keished out this week?"
Guy B:"Man, my dog died on monday,"
4 - "After staying up late last night, I'm keishing out the whole of today."
5 - Wife:"Our car has been stolen!"