Green’s Dictionary of Slang

cop n.2

[cop v. (2)]

1. [late 19C+] a successful bet; thus ext. as any form of ‘sure thing’ or certainty.

2. [20C+] (Aus./N.Z.) a good job obtained by shrewdness or luck; an agreeable proposition; a bit of luck or a trick that leads to large profits; often ext. to soft cop

3. [1910s] (Aus.) an experience.

4. [1930s] (US tramp) a theft.

5. [1940s] (US Und.) the money that confidence men allow a victim to win.

6. [1950s+] (US) an acquisition.

7. [1960s] (US black) an act of sexual intercourse.

In phrases

no cop (also not much cop, any cop)

[late 19C+] of no or little value or use, worthless.

soft cop (n.)

[1921s+] (Aus.) anything seen as easy; esp. in phr. be on a soft cop, to have it easy.

sure cop (n.)

[20C+] (Aus.) an absolute certainty, a ‘sure thing’, a ‘dead cert’.