Get into some dysentery (5)
I believe the answer is:
enter
'get into' is the definition.
(synonyms)
'some dysentery' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'ENTER' is hidden within 'dysentery'.
(Other definitions for enter that I've seen before include "cross the threshold" , "Enrol" , "Come/go in" , "Fruit drink" , "Fill in" .)