Dinkum as a noun means work, especially hard work. As an adjective, like fair dinkum, it means honest or genuine. Other than saying it's chiefly Australian and New Zealand, the OED simply says ...
Here in Missouri, most people born here pronounce the state as /mi.'zuɹ.ə/ (instead of /miz.'uɹ.i/ or something like it). This is a lot more noticeable in the south/central, rural parts of the state. ...