Fresh start for dimwit in Oz (5)
I believe the answer is:
ounce
'oz' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for ounce that I've seen before include "Weight; big cat" , "Wild cat or light weight" , "Twelfth of a pound" , "On cue (anag.)" , "A light weight - feline" .)