Green’s Dictionary of Slang

old man n.

1. of a male.

(a) [late 17C+] a woman’s husband.

(b) [mid-18C; late 19C+] (also man) the penis.

(c) [early 19C+] a father.

(d) [mid-19C+] (also old son) a general greeting or form of address given to a man (usu. one whom one knows), occas. to a woman.

(e) [1940s+] (Can./US) a boyfriend or lover, incl. a homosexual one.

(f) [1950s+] (US) a pimp.

2. [early 19C+] (Aus.) a mature kangaroo.

3. constr. with the.

(a) [early 19C+] (orig. US) any senior figure, the boss, a commanding officer; a headmaster.

(b) [late 19C] in cards, the King.

(c) [1900s–50s] (US, also Old Bloke) God.

4. [1930s] (US) a piece of piping used as a weapon.

In compounds

old man Mose (n.) [abbr. Moses; biblical imagery, via spirituals/hymns] [1940s] (US black)

1. time.

2. death.

old man’s milk (n.)

1. [early 19C] wine.

2. [mid-19C+] whisky.

In phrases

give the old man his supper (v.)

[19C+] of a woman, to make herself available for sex.

old man has his Sunday clothes on (also in one’s Sunday best) [freshly laundered Sunday clothes were stiff with starch]

[19C] a phr. used of the penis, when erect.