Hack writer

On the back of one of the books written by the late Canadian writer, Mordecai Richler, there is a sentence which goes: "an academic turned hack writer". What is a hack writer?

From Merriam-Webster online 3b:

Main Entry: 3hack
Function: noun
Etymology: short for hackney
Date: circa 1721
1 a : a horse let out for common hire : a horse used in all kinds of work b : a horse worn out in service : JADE c : a light easy saddle horse; especially : a three-gaited saddle horse d : a ride on a horse
2 a : HACKNEY b : TAXICAB : CABDRIVER
3 a : a person who works solely for mercenary reasons : HIRELING b : a writer who works on order; also : a writer who aims solely for commercial success

To call someone a "hack" writer means he or she just grinds out the work for money. Also, it implies that the writing is poor or just adequate.

Thanks for the clear explanation!

The word 'Hackney', in the horse sense, is an anglisisation of a Dutch word. The first horses used for taxi cabs in London were of Dutch origin. I can't recall their Dutch name, but it soon turned into 'hackney'in English and the taxis themselves were called 'hackney carriages' - a term still used for a certain type of taxi in Britain. The horses then became 'hacks' - used for repetitive journies requiring little or no inititiative - just like the work some journalists are said to do!!