An amusing story from the Austin Statesman:
Y’all already all know that Texas is known for its slang. The state is home to a slew of Southern colloquialisms as well as totally unique sayings you won’t hear anywhere else. But did you know that the word “Texas” is in itself a slang word? According to Texas Monthly, Norwegians have long used the word “Texas” in lieu of the word “crazy.” To explain the language phenomenon, Texas Monthly cited a Tumblr which claimed that Norwegian slang word has a lot to do with its association to the wild west and Western shoot-em-up movies. Another web travelogue we found on the internet explained it this way: “In Norwegian, ‘texas’ means mayhem and chaos, as in cowboys punching each other and breaking chairs over each other’s heads.” In a Reddit string entitled “Norwegians on Texas,” one Reddit user wrote that when he uses the expression “Det var helt Texas,” he pictures a “cowboy crashing a party and shooting two revolvers into the air.”
The usage apparently dates back to the 70s.