Assembly standards waiving hospital study of intake (9)
I believe the answer is:
dietetics
'study of intake' is the definition.
(study of food intake)
'assembly standards waiving hospital' is the wordplay.
'assembly' becomes 'diet' (term for a parliamentary assembly in some nations).
'standards' becomes 'ethics' (ethical standards).
'waiving' is a deletion indicator (waive can mean to give up).
'hospital' becomes 'h' (abbreviation for hospital on maps).
'ethics' with 'h' removed is 'etics'.
'diet'+'etics'='DIETETICS'
(Other definitions for dietetics that I've seen before include "food intake study" , "Study of nutrition" .)