One thing I dislike the most is a slacker. 
me too a slacker by definition is someone who avoids work and basically has no work ethic
I'm actually going through that now with someone at work who definitely lacks work ethics. 
That is so hard especially knowing they get paid the same as you and you are working, it is not know for sure but the term started either in 1790 or 1898
Exactly and I  think it is out rages like you are getting paid to do nothing at all there are some hard working people in the world and slackers make them look bad or try to.
during ww 1 they used the term to describe those who dodged military service
So they actually had people in the military that would dodge work.
term was also used during the World War II period in the United States. In 1940, "Time" quoted the U.S. Army on managing the military draft efficiently: "War is not going to wait while every slacker resorts to endless appeals."
Evolution.
The shift in the use of "slacker" from its draft-related meaning to a more general sense of the avoidance of work is unclear. In April 1948, "The New Republic" referred to "resentment against taxes levied to aid slackers"
Slacker
A slacker is someone who habitually avoids work or lacks work ethic.
Origin.
According to different sources, the term "slacker" dates back to about 1790 or 1898. "Slacker" gained some recognition during the British Gezira Scheme in the early to mid 20th century, when Sudanese labourers protested their relative powerlessness by working lethargically, a form of protest known as "slacking".
World wars.
In the United States during World War I, the word "slacker" was commonly used to