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2.
A scrawny little fuck that has balls bigger than a bull moose. This person can talk ridiculous amounts of shit and do ridiculous things and 90% of the time get away with it.
Nicky is a SICKRAT.
What a fuckin SICKRAT
by ballsy guy May 06, 2007
 
1.
Most commonly used in Australia. Can be used as an insult to anybody, but generally laid off at your friends or acquaintances in a jokingly manner.

Can also have the potential for appraisals, such as another Australian colloquialism fully sick('fully sick, mate' after can be used as well).
"Your such a sick rat."
OR
"Your such a sick rheeet" (emphasize on the rat to show even more disgust)
by Jonathan.M October 22, 2007