Green’s Dictionary of Slang

(US) a euph. for damned adj.

1867		Rosa Fielding 6: Harriette Heavely went a-walking in Snugcroft woods with one of the danged soger officers, and when she got home her white petticoats was all green with damp grass.
1886		Aberdeen Jrnl 8 May 8/7: Danged if they didn’t all jump overboard and swim for land.
1887		‘Lawrence Lynch’ Mountain Mystery 155: I came mostly on a danged old yaller mustang, but the critter flopped me off [...] So I hoofed it in.
1948		H. McCoy Kiss Tomorrow Goodbye in Four Novels (1983) 99: Late getting away from the plant this morning [...] Danged bottle-washing machine busted.
1963		W.C. Anderson Penelope 183: Suddenly the dangdest mess of radio and radar antennas blossomed out on the deck of that sub.
1972		D. Jenkins Semi-Tough 52: The danged old football’s just not round.
1986		J.B. Keane Bodhrán Makers 233: You stood there like a danged dummy and let me do all the talking.