Loser is ordering a snack (7)
I believe the answer is:
rissole
'a snack' is the definition.
(I know that Rissole is a type of snack)
'loser is ordering' is the wordplay.
'ordering' indicates an anagram.
'loser'+'is'='loseris'
'loseris' with letters rearranged gives 'RISSOLE'.
(Other definitions for rissole that I've seen before include "Losers I find in the chopped meat dish" , "Fried meat dish" , "Sil rose for the meatball" , "Small pastry" , "Minced meat or fish deep fried in egg and breadcrumbs" .)