Look embarrassed with worry on returning (6)
I believe the answer is:
gander
'look' is the definition.
(informal term for a look or glance)
'embarrassed with worry on returning' is the wordplay.
'embarrassed' becomes 'red' (someone may blush or go red when embarrassed).
'with' is a charade indicator (letters next to each other).
'worry' becomes 'nag' (nagging is a kind of worrying).
'on returning' shows that the letters should be reversed in order.
'red'+'nag'='rednag'
'rednag' written backwards gives 'GANDER'.
(Other definitions for gander that I've seen before include "Male 7 across" , "Ranged over the bird" , "Ranged about with male goose" , "Butchers - goose" , "Looking at something - ranged (anag)" .)