Pertaining to the stomach (7)
I believe the answer is:
gastric
'pertaining to the stomach' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for gastric that I've seen before include "Pertaining to the stomach" , "Relating to or involving the stomach" , "Stomachic" , "touching stomach" , "Abdominal" .)