Moderate ebb and flow from a writer (4)
I believe the answer is:
neap
This might be a double definition.
'moderate ebb' is the first definition.
'neap' can be an answer for 'ebb' (thesaurus). I am not certain of the 'moderate' bit.
'flow from a writer' is the second definition.
'neap' can be an answer for 'flow' (thesaurus). I am unsure of the 'from a writer' bit.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for neap that I've seen before include "Least in difference between high and low tides" , "A less than average tide" , "Tide sketched by a pen" , "Sort of tide" , "The middle-sized tide" .)