One impressed by potential titles? (7)
I believe the answer is:
elitist
'one impressed by potential titles?' is the definition.
Although both the answer and 'titles?' are nouns, they are not in the same form of the noun.
'one impressed by potential titles?' is the wordplay.
'one' becomes 'I' (Roman numeral).
'impressed by' indicates putting letters inside.
'potential' indicates anagramming the letters (another potential order of the letters).
'titles' is an anagram of 'eltist'.
'i' put inside 'eltist' is 'ELITIST'.
(Other definitions for elitist that I've seen before include "One feeling superior" , "Favouring a select group" , "No egalitarian" , "Favouring high society" , "Looking down on others" .)