(exclaimation) Oldcootism used during great consternation or surprise. Used by 1890’s prospectors, cantankerous old farmers, and young people playing old people on TV in the ‘60’s and ‘70’s.
Them dern aliensruined my golldarn rubbarb patch with their flyin' machine, dagnabbit!
When one gets upset at something or someone than decides not to take "the man upstairs" name in vain therefore blurting out "Dag nammit". Also used by midwest rednecks.