Dang it!, 4 letters
Dang-blasted, 4 letters
Doggone!, 4 letters
Heck!, 4 letters
Kin of Heck!, 4 letters
Kin of Shucks!, 4 letters
Rats!, 4 letters
Rural Rats!, 4 letters
Shucks, 4 letters
Yer ___ tootin'!, 4 letters