It is a derogatory term used against people from the future. The term gooback came from the fact that when they travel thru the time portal a side affect causes them to be covered in goo, hence the term gooback.
I just want a double cheeseburger you fucking gooback!
Person who arrived via time portal from the year 3045 to escape the harsh conditions of that era. A blend of all present-day races and speaks a language that is a mixture of English, Turkish, Chinese etc. Tends to work for extremely low wages, displacing hard-working present day Americans. Time-traveling had left them with goo on their backs. See also wetback.
("wentback" would have made sense without the need for goo.)
"That mother-fucking gooback took my $140K-a-year logistics job for 90 cents an hour!"
Time traveling immigrants from the future that come to the past looking for work. They work for so little that they take the people of the present's jobs. They put their money in a savings acount so that in the future it will be worth billions of dollars. Their language and race are the mixture of every race in the world.
Chad: I've been working at my job for 14 years now and these Goobacks come in and do my job barely any money. They took my JAWB!!