The usual loss leader at the greengrocer's? (7)
I believe the answer is:
parsnip
'leader at the greengrocer's?' is the definition.
I can't tell whether this definition defines the answer.
'the usual loss' is the wordplay.
'the usual' becomes 'par' (par for the course).
'loss' becomes 'snip' (I can't explain this - if you can you should give a lot more credence to this answer).
'par'+'snip'='PARSNIP'
Can you help me to learn more?
(Other definitions for parsnip that I've seen before include "Pips ran oddly through the vegetable" , "Pale carrot-like vegetable" , "Tapering vegetable" , "Yellow root vegetable" , "Plant with edible white root" .)