Where most people are held back in appraisals (4)
I believe the answer is:
asia
'where most people are' is the definition.
(continent home to the majority of humanity)
'held back in appraisals' is the wordplay.
'back' shows that the letters should be reversed in order.
'held' indicates a hidden word.
'aisa' is hidden in the letters of 'in appraisals'.
'aisa' written backwards gives 'ASIA'.
(Other definitions for asia that I've seen before include "A is A (anag)" , "Continent in which India is situated" , "Tigers found here" , "space for economic expansion?" , "lands in the east" .)