Green’s Dictionary of Slang

(orig. US) naturally.

1942		L.A. Times 29 Nov. (This Week Mag.) 9/4: ‘Natch,’ said the man on the bench to the old one, ‘it was a pity to keep the people waiting. But no great harm done.’.
1948		J. Archibald ‘Klump a la Carte’ Popular Det. July 🌐 ‘We know conditions there are abdominal and—’ ‘Natch,’ Willie interrupted.
1958		Southern & Hoffenberg Candy (1970) 153: Natch I was hip to the lay the moment I dug his joint.
1961		K. Amis letter 5 Apr. in Leader (2000) 587: [It] has that red-headed Papist thug (confidential, this, natch) high up in its hierarchy.
1970		T. Southern Blue Movie (1974) 18: I hate the fucking Swedes. Except for Bergman, natch.
1988		D. Woodrell Muscle for the Wing 66: I dig gamblin’, too, and natch I love my tunes.
1994		G. Indiana Rent Boy 67: He’s married, natch, with kids.
2004		C. Brookmyre Be My Enemy 98: Unlike that nasty cokehead brother of his, natch.