Male after one-fifth off fast food (6)
I believe the answer is:
quiche
'food' is the definition.
(quiche is a kind of food)
'male after one-fifth off fast' is the wordplay.
I cannot quite see how this works, but
'male' could be 'he' and 'he' is found within the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for quiche that I've seen before include "Egg dish" , "Savoury tart with egg-based filling" , "Savoury egg-based flan" , "Cheese and bacon pastry dish" , "Open tart with savoury egg filing" .)