Old exercise and food regime inspiring new, practical method (9)
I believe the answer is:
expedient
'inspiring new practical method' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'old exercise and food regime' is the wordplay.
I cannot really understand how this works, but
'old' could be 'ex' (prefix meaning former or onetime) and 'ex' is found in the answer.
'exercise' could be 'pe' (Physical Education) and 'pe' is located in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is found within the answer.
'food' could be 'diet' (diet is a kind of food) and 'diet' is found in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for expedient that I've seen before include "scheme" , "Appropriate, convenient" , "Suitable - practical - device" , "Extend pie - it is suitable for its purpose" , "Advantageous in a given situation" .)