Look, a goose! (6)
I believe the answer is:
gander
I believe this is a double definition.
'look' is the first definition.
(informal term for a look or glance)
'a goose' is the second definition.
(gander is a kind of goose)
(Other definitions for gander that I've seen before include "Male goose; look (colloq.)" , "Male bird - look" , "town in Newfoundland" , "male member of the Anatidae family" , "Goose sauce is good for it" .)