Question one aspect under adjustment of rent (9)
I believe the answer is:
interview
'question' is the definition.
(I know that question can be written as interview)
'one aspect under adjustment of rent' is the wordplay.
'one' becomes 'i' (Roman numeral).
'aspect' becomes 'view' (synonyms).
'under' means one lot of letters go next to another (below, in a down clue).
'adjustment of' indicates anagramming the letters (I've seen this in other clues).
'rent' is an anagram of 'nter'.
'view' after 'nter' is 'nterview'.
'i'+'nterview'='INTERVIEW'
(Other definitions for interview that I've seen before include "to ask questions" , "Formal discussion with job seeker" , "official meeting" , "encounter" , "Formal discussion with a job applicant" .)