Brigand, ergo, has a look (6)
I believe the answer is:
gander
'a look' is the definition.
(informal term for a look or glance)
'brigand ergo has' is the wordplay.
'has' indicates a hidden word.
'GANDER' is hidden within 'brigand ergo'.
(Other definitions for gander that I've seen before include "waterbird" , "'What's sauce for the goose is sauce for the . . . . . .'" , "town in Newfoundland" , "Ranged about with male goose" , "A butcher's -- bird" .)