Green’s Dictionary of Slang

lamb n.1

[note Williams for 17C use of lamb as a novice whore]

1. [mid-17C–1960s] a simpleton, a fool, esp. one easily cheated of their money; also attrib.

2. [mid-19C] a prostitute.

3. [late 19C] a rough, a thug.

4. [1920s–70s] (mainly US prison, also kid lamb) a young homosexual boy, esp. one who accompanies a tramp.

5. [1940s+] (US black) an innocent.

In compounds

lamb-brained (adj.)

[2000s] (N.Z.) weak, stupid.

SE in slang uses

In compounds

lamb and spinach (n.)

[mid-19C] (UK Und.) women and gin.

lamb cannon (n.)

[1990s+] the penis.

lamb chop (n.)

[1970s+] a term of affection; usu. of a woman, occas. a man.

lamb-pie (n.) [a pun on the SE lamb/lam v.1 (1)]

[late 17C–early 19C] a beating, a flogging.

lamb pit (n.)

[1950s–70s] the vagina.

lamb sauce (n.)

[mid-19C] (UK Und.) fine clothes.

lambskin man (n.) [the ermine-bordered robes]

[late 17C–mid-19C] a judge.

lamb’s tongue (n.) [1930s–40s] (US prison)

1. $1.

2. a $5 bill.

In phrases

fresh lamb (n.)

[mid-19C] (UK Und.) a new prostitite.

holy lamb (n.) [a pun on Lat. agnus dei, the lamb of God, used as the first words of the Catholic mass. The term lamb was given to the particularly violent troops led by the soldier of fortune Colonel Percy Kirke in 1684–6. Their flag carried an image of the paschal lamb, known in heraldry as the holy lamb, and the troops were known as ‘Kirke’s lambs’. Lambs also referred to gangs of thugs used to intimidate voters at 19C elections, e.g. the ‘Nottingham lambs’, which flourished 1860–70]

[late 18C–19C] (Irish) a complete and utter villain.