Green’s Dictionary of Slang

1. (UK Und.) a lookout, one who does not go inside the burgled house.

1865		Leaves from Diary of Celebrated Burglar 13/2: It was here agreed upon that Joe should be the outsider, and Jack and myself go in.
1901		J. Flynt World of Graft 93: I had to keep watch outdoors [...] A fellow that does that an’ pipes off places that are to be touched up is called an outsider.

2. (US Und.) in pl., a device for unlocking a door by manipulating the key through the keyhole.

1846		Nat. Police Gaz. (NY) 18 July n.p.: [as used by hotel thieves] Terrible instruments called outsiders – resemble pair of long pincers.
1848		Ladies’ Repository (N.Y.) Oct. VIII:37 316/2: Outsiders, an instrument to unlock a door with its own key.
1909		F.H. Tillotson How I Became a Detective 94: Outsiders – A pair of nippers to turn keys from the outside.
1927		Clark & Eubank Lockstep and Corridor 174: Outsiders—long-nosed pincers used on the outside to turn a key which is on the inside of a door-lock.
1950		Goldin et al. DAUL 150/1: Outsiders. [...] 2. Narrow pincers used to turn a key in a lock from the outside.

3. a person who is considered socially inferior, esp. as rank outsider, a complete and utter inferior.

[1860		Hotten Dict. of Modern Sl. etc. (2nd edn) 184: OUT-SIDER, a person who does not habitually bet, or is not admitted to the ‘Ring’].
1868		Sportsman 8 Feb. 2/1: Notes on News [...] The ‘rank outsiders’ who read in the papers juicy reports of the hippophagic feast, are much in the position of the Peri at the gates Paradise.
1877		W. Black Green Pastures & Piccadilly 146: Of course it was as a mere pleasure excursion that we outsiders were permitted to speak of this long journey .
1895		C. Crowe Aus. Sl. Dict. 55: Outsider, not of our party.
1895		‘Harry on ’Arry’ in Punch 17 Aug. in P. Marks (2006) 24: I’m sure he’s a bloomin’ outsider.
1904		Marvel 12 Nov. 7: They’re both rank outsiders – Nibbley and old Daddy Sykes.
1939		P. Hamilton To The Public Danger 75: cole: (with furious irritability). Will you stop calling me ‘mate’! fred: But, listen, pal— cole: I am not your pal! You little outsider!

4. (Irish) a mentally deficient person.

1960

J. O’Donoghue In Kerry long Ago n.p.: Sun stroke [...] upset his ind [and] he was brought down to the chapel with others called ‘outsiders’ for instruction in the catechism [BS].

5. (Aus. / US Und.) an outside pocket.

1849		Bell’s Life in Sydney 30 June 3/2: One Joseph Lyons was charged by one Mr. Fairweather with having abstracted his silk pocket handkerchief [...] from its legitimate resting-place in his pilot outsider.
1914		Wash. Post 11 Nov. Misc. 3/4: He is never wanted in society skilled or practiced enough to take a ‘bug’ [...] or a ‘left breech’ or an ‘outsider.’.

6. (Aus. prison) one who has never experienced a prison sentence.

1984

B. Ellem Doing Time 132: [T]he joke that went around was ‘did you hear about the who got a brick and couldn’t handle it?’ [...] if they told it to an outsider they would wonder what the hell you were talking about.

7. (US) an act of sexual intercourse performed out of doors.

1985

J. Briskin Too Much Too Soon (1986) 444: ‘We could swing right here,’ she said. Since the afternoon of the outsider, they had made love only once.