Green’s Dictionary of Slang

(a) (orig. racing, also p, peanut) the ideal, the perfect choice, the favourite [horseracing pea, the favourite; ult. from the pea in the game of thimble-rig, played with three inverted thimbles and a pea].

1880		Adelaide Obs. (SA) 25 Dec. 1/3: [P]ossibly the Morphettville running between Sir Charles, Silverthread, and Aurora may disclose the real pea for at least two of the Adelaide Racing Club handicaps.
1884		H. Smart Post to Finish I 149: It’s a rum go, and which is the real pea I’m blest if I know.
1896		Australasian (Melbourne) 5 July 13/5: [A]s Mr. Miller does not wear his heart upon his sleeve for daws, or pressmen, or the public to peck at, there is not much likelihood of finding out which is the ‘pea’ until the sable money goes on.
1900		Bulletin (Sydney) 29 Sept. 24/2: Trainer Scobie might have a better one in his stable, which includes The Bride and La Carabine, and latter might be the ‘k’rect pea.’ Punters should be careful.
1906		Sun. Times (Perth) 14 Jan. 4/8: Tommo soon became the abserlute peanut. Even the tarts oo could swim and dive and flote took lessons off ’im.
1911		E. Dyson ‘The Big Spoof’ in Benno and Some of the Push 206: Mr. Dickson [...] ran his eye down the card and chanced it. ‘Dandy’s the P,’ he said. ‘Put yer whole week’s wash on Dandy.’.
1915		Sport (Adelaide) 8 Jan. 5/4: [of a (desirable) young woman] Dick S. [...] /Was chatting the pea on the ‘Hill,’ / Is he going to do his nut / And marry that short Mill.
1916		Sun. Times (Perth) 24 Dec. 2s/4: Old stand-no-folly Jenkins / Who saved the day for every racin’ pea!
1930		L. Lower Here’s Luck 57: ‘That’s it,’ gabbled Eggs. ‘That’s the pea’ .
1951		D. Stivens Jimmy Brockett 252: Any doubts I’d had about him being the pea for the job were all gone now. He was so much the mucking crusader.
1958		F. Hardy Four-Legged lottery 190: ‘I’ll tell yer, I’ve got the tip about it. Old Dapper Dan earwigged at the track. Swordsman is the pea’.
1966		J. Holledge Great Aus. Gamble 36: He invested £750 of his ‘roll’ on a horse he considered a ‘good thing’ in the opening race. However, [....] for one his good judgement was astray. The best his ‘pea’ could do was finish a moderate second.
1980		K. Garvey Shout for an Adder 141: ‘The whole local mob’s goin’ to back the old feller,’ Sidwell said knowingly, ‘and as you’re my number one jock they’ll naturally think you’re on the goer. But Beanstalk will be the pea.’.
1996		Ozwords Oct. 🌐 pea a favourite; a likely winner, especially as chosen by a stable which has a number of runners in a race.
2013		T. Peacock More You Bet 35: The ‘favourite’ might also be referred to as ‘the fave’ [...] or the ‘bird’ or the ’aviary’ or ‘the pea!

(b) in weak use, a man.

1905		Bulletin (Sydney) 21 Sept. 40/1: Rows! Now I’ll tell yer wot causes them. P’r’aps a pirate’ll bring some other pea’s lot ter the room ’n’ label her for every darnce on the bill. ’Er failin’ gets ter ’ear about it ’n’ turns up late, full o’ beer ’n’ bad ideas, ’n’ demands a settlement.
1905		Westralian Worker (Perth) 10 Nov. 8/2: ‘Wot’s them peas kiddin’ ‘emselves they’re doin’ over there?’ he asked, pointing to a crowd on the Recreation Ground.
1906		Sun. Times (Perth) 23 Sept. 4s/4: ‘I wish,’ sez she, ‘that this barmy pea ’ad a bit of life about ’im’.
1912		Bulletin (Sydney) 11 July 32/2: ‘What about your friends?’ I asked as I handed him his coat. ‘Oh! they’ll be in soon,’ he said. ‘We wanted to make sure that pea was a mug.’.
1924		E.G. Murphy ‘’Is ’Arp’ Dryblower’s Verses 10: A pommy pea named ’Arry ’Urst, / But two years out in Aussie-land, / Went on a roarin,’ ragin’ burst.
1929		Sun. Times (Perth) 10 Nov. 65/8: I’m drivin’me Jack McNab down the field of wheat, an’ I makes a swipe at the applesauce with me egg-flip and I cops a pea over the dial.

(c) someone in a favourable position, e.g. as a lover; a superior person.

1906		E. Dyson Fact’ry ’Ands 101: Lummie, the pea was full iv contrition [...] ’n’ he coundn’ be too good er mother t’ me.
1906		Sun. Times (Perth) 16 Sept. 4/7: I’m pinched by a burly pea jist as I’m gettin’ away with a bag of marines from a woodshed.
1907		Sun. Times (Perth) 19 May 1/1: As soon as the amorous bladder-booter is stiff the curly-headed waiter is the pea.
1913		Sport (Adelaide) 14 June 7/4: They Say [...] That S.R. was seen talking to a flash pea Saturday afternoon.
1924		Sun. Times (Perth) 10 Aug. 17/1: The pea who happened to be president [...] acted as a true patriot.
1969		A. Buzo Rooted III iii: He’s had his eye on her for some time, you know, but I’m the pea, she said.
1989		A. McGregor Wally and the Broncos 94: ‘I thought someone like Bobby McCarthy would be considered the pea’.
1996		Ozwords Oct. 🌐 pea [...] has developed an extended sense: someone in a favoured or favourable position; a person expected to win a job etc. over other applicants.