Green’s Dictionary of Slang

lob n.2

also lobb
[16C–19C SE/dial. lob, a country bumpkin. Note Yid. lobbes, rascal + Du. lobbes, a clown]

1. (UK Und.) an informer.

[UK] ‘The Slap-Up Cracksman’ Swell!!! or, Slap-Up Chaunter 42: Who would be a lob or stag? / And splitting, wag his d—d red rag.

2. a dull, stupid person; thus lobbery, stupidity, lobbish adj., stupid.

[[Ire]Stanyhurst ‘Of A Craking Cvtter’ in Of Virgil his Æneis (1836) 148: His minion, with carnal wantones itching, Chooste for a freend secret no worse, then a countrye lob heerd swayne].
[US]Eve. Statesman (Walla Walla, WA) 5 Mar. 3/3: As for the Stew, he is a Boob or a Lob who, in addition to his Boobery or Lobbery, adds the speciality of inebriety.
[US]B. Fisher A. Mutt in Blackbeard Compilation (1977) 21: Take my tip and duck, you big lob, while you’re all together.
[Aus]Sport (Adelaide) 1 Nov. 6/3: Just as well for the big lob as he might have received a poke .
[US]Jackson & Hellyer Vocab. Criminal Sl. 55: lob [...] An awkward craftsman; a delinquent; an opprobrious character among thieves.
[US]T.A. Dorgan Indoor Sports 4 June [synd. cartoon] That guy — why he was the biggest lob I ever saw — He didn’t know that Wilson was President or that Washington was dead except from hearsay.
[US]Washington Times (DC) 12 Nov. 32/6: In this business we meet up with a lot of them lonesome lobs.
[US]D. Runyon ‘Madame La Gimp’ in Runyon on Broadway (1954) 241: The proud old Spanish nobleman does not wish his son to marry any lob.
[US]Monteleone Criminal Sl. (rev. edn).
[US]R. Prather Darling, It’s Death (2003) 35: Who’s the ugly lob at the end of the bar chilling us? He’s dogging me. Doesn’t seem to care if I know it or not.
[US]J. Scarne Complete Guide to Gambling 684: Lob – a hanger on around gambling joints [...] also called a Jerk.
[US](con. 1998–2000) J. Lerner You Got Nothing Coming 339: ‘The elevators on their wing are jammed with dot-com gazillionaires’ [...] ‘Those fucking lobs can find the elevators?’.

3. (Aus./UK Und.) a police officer, esp. an officious one.

[Aus](con. WWI) A.G. Pretty Gloss. of Sl. [...] in the A.I.F. 1921–1924 (rev. t/s) n.p.: lob. A Policeman, one who goes out of his way to report breaches of discipline or law.
[UK]R. Llewellyn None But the Lonely Heart 250: ‘Lobbo,’ one of them shouts, ‘Coppers.’ .

4. (US Und.) an initiate into criminality.

[US]Howsley Argot: Dict. of Und. Sl.

5. (US prison) a deliberate insult implying that the subject is weak and/or homosexual; a spur to a fight.

[US]Bentley & Corbett Prison Sl. 35: Chump A derogatory term for a male inmate meaning he is homosexual and or weak. [...] (Archaic: lob).