Before computing added new meanings to the word hack, the meaning I associated most commonly with it was “a writer who churns out unimaginative writing for hire.”
This use of the word hack derives from the horse rental industry.
Hack is the shortened form of hackney, a word that entered English from French haquenée, “a small horse suitable for ordinary riding.” In The Canterbury Tales (c.1368), Chaucer describes the Canon’s Yeoman as riding “a dapple-gray hackney.”
From meaning a type of horse, hackney came to mean a rented horse.
Because hired horses were overworked, hackney and hack came to mean any person employed in servile, tedious, and tiring work.
As an adjective, hackney meant “worn out by indiscriminate or vulgar use.” One could speak of “a hackney proverb” or “a hackney plot.” In modern English, the adjective with this meaning is hackneyed:
His [Dreiser’s] hackneyed and clichéd diction occurs frequently when he is not engaged in a form of indirect discourse, as in his description of the New York theatre district.
By the 18th century, the noun hackney had been shortened to hack and could mean either “a hired horse” or “a hired carriage.” In the United States, hack is still used as a word for taxicab.
By the 1770s, hack had taken on the meaning of “a literary drudge, who hires himself out to do any and every kind of literary work; hence, a poor writer, a mere scribbler.” It is still used with this sense by speakers who grew up before the word became associated with computing:
There is hack fiction all over the best seller list so nothing new there.
[James] Patterson belongs in his own category, reserved for the hacks committed to hacking every day. [Peter] Brown is a lesser hacker.
Journalists have long been referred to as hacks because they must produce daily content on a variety of subjects.
The application of the word hack to prolific, high-earning novelists scorned by literary critics has produced a backlash against the pejorative use of the word hack.
Writing in The Guardian, David Barnett demands “What’s wrong with being a hack?” He reminds readers that literary giant Samuel Johnson declared “No man but a blockhead ever wrote, except for money.” Barnett sees nothing wrong with being “prolific, inventive, writing for a populist mass-market readership” and making money for it.
Attempts to redefine hack as it applies to writers of fiction can only be wasted effort. The word has become too closely associated with computer use and new terminology is growing up to describe a new kind of writing:
“Hacker journalists” are computer programmers who assume roles as journalists in order to affect social change.
Unlike the traditional hack writer who writes only for monetary gain, “hacker journalists” pursue non-monetary rewards and seek personal fulfillment through moral interventionism. —“Muckraking in the Digital Age: Hacker Journalism and Cyber Activism in Legacy Media,” by Bret Schulte, and Stephanie Schulte, Mediac, The Journal of New Media and Culture, Volume 9, Issue 1)
I guess we’ll just have to come up with a new term for “an unimaginative writer who will write any kind of drivel for money.”
“Hackney carriage” is still a term for a London Taxi with drivers being members of the Hackney Carriage Guild.
And of course the most well-known recent example of “hack” is Michael Jordan on President Obama as a golfer: “He’s a hack.”
You neglected to mention the popular term “political hack” used to describe various “backroom boys” and other nefarious characters whose sole function is to keep politicians in the halls of power by whatever means necessary, legal or otherwise.
The term hack in computers is pretty close to the one for writers. A hack is a quick and dirty program, or modification of a program. Something the developer might not be proud of but it works because it is needed _right now_. There is usually an intent to do a more professional version later unless the overall program is just needed once.