It is no good ~ It doesn't work ~ It's useless; You can't use it; It's ineffective.Originally Posted by bread
It is not good ~ It's bad.
The food is not good. (The food is bad/not good to eat)
The food is no good. (The food has spoiled)
What are you up to (right now/these days)?
=> What are you doing right now; What have you been doing lately? :D