Green’s Dictionary of Slang

1. baggage, esp. carried by a tramp or a sailor.

1849		J.F. Cooper Sea Lions Ch. v n.p.: Not only was the chest more than half empty, but the articles it did contain were of the coarsest materials [...] ‘What is to be done with all this dunnage, deacon?’ [F&H].
1864, 1867, 1870		Hotten Sl. Dict.
1875		Jasper Wkly Courier (IN) 1 Oct. 6/2: When I woke out of that drunk I found that the ship [...] had carried all my dunnage with her.
1882		Sydney Sl. Dict. (2 edn) 3: Dunnage - Baggage, clothes.
1885		J.S. Borlase Blue Cap, the Bushranger 96/1: Swell dunnage he had brought with him from California.
1889		Western Dly Press 6 Feb. 3/2: At present we are getting [...] 22 degrees of frost; so we have commenced to haul over our dunnage bags and winter clothes.
1902		Bulletin (Sydney) 13 Dec. 21/2: She hadn’t brought much dunnage aboard with her, barring a concertina and a few hairpins and things tied up in a handkerchief.
1908		E.S. Sorenson Quinton’s Rouseabout and other Stories 92: Then Noel picked up his dunnage an’ left, an’ we never saw any more of him from that day to this.
1909		Observer (N.Z.) 27 Nov. 51/3: The arrival of his dunnage too, at the local pub caused the eyes of old Smirks, the licensee, to bulge.
1921		N&Q 12 Ser. IX 384: Dunnage-Bag. Canvas bag to carry clothing.
1922		P.A. Rollins Cowboy 153: If he had further personal belongings – and these the West called his ‘plunder,’ as the East termed them ‘dunnage’ or ‘duffle’.
1936		Eve. Teleg. (Dundee) 24 Mar. 9/4: At Cape Town [...] he cleared all his dunnage in time to catch the boat train for the north.

2. clothes.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.
1921		N&Q 12 Ser. IX 384: Dunnage. Clothing.