Digestive movement with vigour (6)
I believe the answer is:
peptic
'digestive' is the definition.
(I've seen this before)
'movement with vigour' is the wordplay.
'movement' becomes 'tic' (I've seen this in other clues).
'with' means one lot of letters go next to another.
'vigour' becomes 'pep' (I've seen this before).
'tic' after 'pep' is 'PEPTIC'.
(Other definitions for peptic that I've seen before include "of the digestive system" , "Kind of ulcer in stomech or duodenum" , "This ulcer is in the stomach or duodenum" , "Relating to digestion - kind of ulcer" , "Of digestion, and a related ulcer" .)