Nice groom is upset, made to offer efficient service (9)
I believe the answer is:
ergonomic
'made to offer efficient service' is the definition.
'nice groom is upset' is the wordplay.
'is upset' is an anagram indicator.
'nice'+'groom'='nicegroom'
'nicegroom' anagrammed gives 'ERGONOMIC'.
(Other definitions for ergonomic that I've seen before include "Maximising efficiency" , "Designed for work efficiency" , "Studying man in his work environment" , "Well-designed" , "Designed for efficiency and comfort in the working environment" .)