Grand, upright character in Catholic circles (7)
I believe the answer is:
homeric
'grand' is the definition.
'upright character in catholic circles' is the wordplay.
'upright character' becomes 'i' (vertical letter of the alphabet).
'in' becomes 'home' ('he's in' can mean 'he's home').
'catholic' becomes 'rc' (I've seen this in other clues).
'circles' indicates putting letters inside.
'home'+'rc'='homerc'
'i' inserted into 'homerc' is 'HOMERIC'.
(Other definitions for homeric that I've seen before include "In style of, eg, the Iliad" , "Such epic style" , "Like unrestrained laughter" , "Imposing" , "of old poet" .)