Troops short of time prescribed treatment (7)
I believe the answer is:
regimen
'prescribed treatment' is the definition.
(I've seen this before)
'troops short of' is the wordplay.
I cannot quite see how this works, but
'troops' could be 'men' (I've seen this in other clues) and 'men' is found within the answer.
This may be the basis of clue (or it may be nonsense).
'time' acts as a link.
Can you help me to learn more?
(Other definitions for regimen that I've seen before include "prescribed treatment" , "Merge in (anag.)" , "Prescribed way of life like diet" , "Systematic way of life" , "Mere gin for a course of treatment" .)