Green’s Dictionary of Slang

pissant n.

[SE pissant, an ant]

1. [1930s+] an insignificant person, a ‘nobody’; thus drunk as a pissant, very drunk; game as a pissant, very brave.

2. attrib. use of sense 1.

In phrases

pissant (around) (v.) [1940s+] (Aus.)

1. to mess around.

2. to defeat, to outwit.