Green’s Dictionary of Slang

1. (Aus.) a spastic, either actual or fig. as a derog. term.

1983		S. May No Exceptions in Best Radio Plays (1984) 116: Right. Today we’re going to run. Not like yesterday. Not like a bunch of spasos and grandmas.
1998		J. O’Connor Salesman 172: Yeah, this spazzo of a priest told us all about it at the Christmas retreat.

2. attrib. use of sense 1.

2006

D. Mitchell Black Swan Green 105: Dawn Madden did a spazzo yokel voice at the tractor.