Green’s Dictionary of Slang

spear v.

1. [20C+] (Aus.) to dismiss from a job.

2. [20C+] (Aus.) to throw, usu. to throw out of a pub, dancehall etc.

3. [1910s–60s] (US, also toss the spear) to beg, to obtain through begging.

4. [1930s–40s] (US prison) to arrest.

5. [1980s] (US Und.) to pickpocket.

6. [1980s+] (Aus. prison, also spear in) to put something or someone in a person’s way.

In phrases

spear a job (v.)

[1940s+] (Aus.) to get a job.