A fast walk (6,5)
I believe the answer is:
hunger march
'a fast' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'walk' is the wordplay.
I cannot really see how this works, but
'walk' could be 'march' (march is a kind of walk) and 'march' is present in the answer.
The remaining letters 'hunger' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for hunger march that I've seen before include "movement that brings protest" , "1936 Jarrow demonstration" .)