Sickening (10)
![Ross](/clue/static/ross-mug.min.png)
'sickening' is the definition.
(I know that sickening can be written as nauseating)
This is the entire clue.
(Other definitions for nauseating that I've seen before include "arousing unpleasant feeling" , "being hard to keep down" , "Revolting" , "Loathsome" , "Stomach-turning" .)
(Other definitions for ailing that I've seen before include "not doing very well" , "Unwell, in poor condition" , "In poor health" , "Sickly, poorly" , "Infertile" .)