Soldier with his own disease (11)
I believe the answer is:
legionnaire
This might be a double definition.
'soldier' is the first definition.
(legionnaire is a kind of soldier)
'his own disease' is the second definition.
The answer is a person as well as being a singular noun. This is suggested by the definition. I also know that 'disease' relates to this answer.
'with' acts as a link.
Can you help me to learn more?
(Other definitions for legionnaire that I've seen before include "French soldier" , "Beau Geste was one" .)