One with no illusions about a catalogue (7)
I believe the answer is:
realist
'one with no illusions' is the definition.
(I've seen this before)
'about a catalogue' is the wordplay.
'about' becomes 'rea' (I've seen this in other clues).
'a catalogue' becomes 'list' (I've seen this before).
'rea'+'list'='REALIST'
(Other definitions for realist that I've seen before include "no Walter Mitty?" , "One seeing things as they are" , "One who sees things in a practical way" , "Pragmatic type" , "Is alert (anag)" .)