Green’s Dictionary of Slang

cobber n.2

also cobs, kobber
[? dial. cob, to take a liking to someone or Heb./Yid. chaver, a ‘pal’, a ‘chum’. Like the other great clichéd Aus. word, bonzer adj., cobber is now nearly defunct]

1. (Aus./N.Z.) a friend, a mate.

Sportsman (Melbourne) 31 July 7/8: My cobber came back to Melbourne disgusted at his mozzel. When we totted it up one night in Auckland, we found the trip had cost us A Couple of Hundred.
[Aus]Queenslander (Brisbane) 16 Aug. 298/3: Australia, we are sometimes told, has no literature of its own [...] If they want to see it in all its pure autochthonousness they should go, not to our books, but to our letters. Take, for instance, that letter of Mr Bloomer’s which was read the other day in the Police Court at Gympie. When Mr Bloomer says [...] ‘Be cobbers till I come back’.
[Aus]Morn. Bulletin (Rockhampton, Qld) 29 June 5/3: There was some further conversation among the men, Morris saying that Dempsey was his ’cobber’.
[Aus]Dubbo Liberal & Macquarie Advocate 21 July 2/2: The prisoners’ outside ‘cobbers’ then tied the tobacco to the lines, which were hauled in.
[UK]W.S. Walker In the Blood 17: Toby Johnson, Billy’s ‘cobber’ or mate.
[Aus]L. Stone Jonah 3: ’Ere, ’old ’ard, ain’t yer goin’ ter interdooce yer cobber?
[US]Rising Sun 8 Feb. 3/2: K is for Kobber, Australian for friend.
[Aus]Aussie (France) 12 Mar. 1/1: He left his rum issue on a table. When he returned [...] he found that a cobber, thinking that it was cold tea, had thrown it out of the window.
[Aus]K.S. Prichard Coonardoo 231: We’re going to be cobbers, old dear, aren’t we?
[Aus]X. Herbert Capricornia (1939) 210: Goowole cobber. Alls a grey yelp.
[NZ]F. Sargeson ‘A Great Day’ in A Man And His Wife (1944) 28: Mary and I used to be great cobbers.
[NZ]N. Marsh Died in the Wool (1963) 169: We’re real pals, aren’t we? [...] Real chums. Cobbers?
[US]J.E. Macdonnell Jim Brady 154: What’s yer monniker, cobs?
[Aus]D. Niland Shiralee 93: I know you two are great cobbers.
[US](con. WWII) B. Cochrell Barren Beaches of Hell 122: If your cobber runs this restaurant you’ll have it good.
[Aus]S. Gore Holy Smoke 65: That shook the Sadducees and the Pharisees and the high priests, and all their frowsy cobbers, rigid.
[UK](con. 1940s) J.G. Farrell Singapore Grip 562: Hop it. You too, cobber.
[Aus]G.A. Wilkes Exploring Aus. Eng. 14: Cobber probably comes from the Suffolk expression to cob, ‘to take a liking to anyone’ – to ‘cobber up with someone’, as we sometimes say.
[UK]T. Jones Curse of the Vampire Socks 26: ‘Right, Cobber!’ said the Kangaroo.
[Aus]T. Winton Human Torpedo 9: Another time, cobbers. I’m off to work.
[Aus]Penguin Bk of More Aus. Jokes 137: The local cop calls a mate. ‘Bad news, cobber.’ [Ibid.] 433: Two cobbers had been humping their blueys out back o’ Bourke for months.
[UK]Guardian Rev. 19 Feb. 2: Good on you, cobber.

2. an Australian.

[UK]K. Amis letter 20 Dec. in Leader (2000) 418: Actually I’m feeling quite friendly towards cobbers for the moment because some digger rag in Melbourne wants to serialise Jim.

In derivatives

cobbership (n.)

the state of (close) male friendship; team spirit, synon. with mateship under mate n.

[Aus]Sun. Times (Perth) 3 Aug. 2: [T]here has been a solid feeling of ‘cobbership’ among them all, and to that I attribute Perth's success.
[Aus]Nambour Chron. (Qld) 16 Nov. 2/7: His cobbership with the Anzacs is a priceless possession, that gold cannot buy or time wither.
[Aus]Truth (Perth) 3 Sept. 7/2: [headline] CASH BEFORE ‘COBBERSHIP.’ Two Mates Fall Out.
[Aus]Teleg. (Brisbane) 2 Oct. 8/5: He [...] has coined a word to describe what he considers the chief characteristic of Australians, ‘cobbership’.
[Aus]Mirror (Perth) 4 Sept. 4/4: [of a woman] I write this par with a sob in my heart and a tear pours out from my pen. This week I lost a lovely pal of years. She sleeps now underneath the sacred soil I have a memory of a cobbership that binds and a memory oi a sweeter yesterday.
[Aus]Camperdown Chron. (Vic.) 28 Apr. 1/3: And so strong were those bonds of 'cobbership' among the men of Anzac that to-day, thirty odd years since the landing on Gailipoli, there is a brotherhood amongst those men that is second to none.

In compounds

cobber-dobber (n.) [dobber n.1 ]

(Aus.) one who informs on a friend.

[Aus]Baker Aus. Lang. (2nd edn).
[Aus]A. Chipper Aussie Swearers Guide 33: If your Grandma’s funeral once again falls on Melbourne Cup day, it’s a cobber dobber who asks the boss if he’s ever counted your deceased grandmothers .
[Aus]Canberra Times (ACT) 9 May 20/7: I heard the police anti-drug campaign Operation Noah referred to as Cobber Dobber Day.