Swallow cocktail the second one's left (6)
I believe the answer is:
martin
'swallow' is the definition.
(I know that martin is a type of swallow)
I don't understand the rest of the clue.
(Other definitions for martin that I've seen before include "Creature that flies" , "Dickens novel featuring Mr Pecksniff" , "Male name, bird" , "Variety of swallow" , "Bird of the swallow family" .)