Empty talk never-ending in nervous condition of the stomach (7)
I believe the answer is:
gastric
'of the stomach' is the definition.
(I've seen this in another clue)
'empty talk never-ending in nervous condition' is the wordplay.
'empty talk' becomes 'gas' (I've seen this before).
'never-ending in nervous condition' becomes 'tric' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'gas'+'tric'='GASTRIC'
Can you help me to learn more?
(Other definitions for gastric that I've seen before include "touching stomach" , "Pertaining to the stomach" , "affecting stomach" , "Abdominal" , "Relating to or involving the stomach" .)