Egyptian god’s very large flag (6)
I believe the answer is:
osiris
'egyptian god's' is the definition.
(Osiris is an example)
'large flag' is the wordplay.
'large' becomes 'os' (abbreviation for oversize).
'flag' becomes 'iris' (type of iris flower).
'os'+'iris'='OSIRIS'
'very' is the link.
(Other definitions for osiris that I've seen before include "Egyptian god of the dead" , "Husband of Isis, father of Horus - sis or I (anag)" , "Egyptian god - sis or I (anag)" , "God, husband of Isis" , "Egyptian deity" .)