Apparently nervous, time being such a ghoulish hour (9)
I believe the answer is:
twitching
'apparently nervous time' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'being such a ghoulish hour' is the wordplay.
I cannot really see how this works, but
'being' could be 'witch' (witch is a kind of being) and 'witch' is found in the answer.
The remaining letters 'ting' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for twitching that I've seen before include "Visibly nervous" , "Showing nervousness" , "Obsessive bird-spotting" .)