Mock something grubby? (5)
I believe the answer is:
scoff
'mock' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for scoff that I've seen before include "Greedily consume" , "Deride - guzzle" , "Speak derisively" , "turtle soup for example?" , "Jeer; eat greedily" .)