What is meant by problems not in NP but in NP hard?
A language $L$ is NP-hard if you can reduce every language in NP to $L$ in polynomial time. For example, the halting problem is NP-hard: if $A$ is any language in NP, say accepted by a nondeterministic polynomial time Turing machine $T$, there there is a polynomial time reduction which accepts an input $x$ and constructs a Turing machine which simulates all computation paths of $T$ on $x$, and halts if and only if any of these paths accepts.

On the other hand, the halting problem is not in NP, since it is not computable. So the halting problem is an example of an NP-hard problem which is not in NP.
You can think of NP-hard problems as being "at least as hard" as all of NP. They are allowed to be even harder.