“Drat” is the aphetic form of the interjection “God rot”, and our chapter 2 derived verb is attested from the 1870s.

• 02.039 and dratting),
• 06.008 then drat him,
• 08.064 You dratted hobbit!
• 09.029 Drat this dwarvish racket!’
• 12.083 Drat the bird!’

“drat, int.” OED Online. Oxford University Press, March 2015. Web. 1 June 2015.