Assimilate quickly and sneer (5)
I believe the answer is:
scoff
'sneer' is the definition.
(I've seen this in another clue)
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 "Deride - guzzle" , "Speak contemptuously or drink informally" , "Mock" , "Greedily consume" , "Jeer - eat quickly" .)