Word Study
jackaroo
CIDE DICTIONARY
jackaroo, n. [Jack + kangaroo.].
A young man living as an apprentice on a sheep station, or otherwise engaged in acquainting himself with colonial life. [Webster 1913 Suppl.]
jackaroo, v. i.
To be a jackaroo; to pass one's time as a jackaroo. [Webster 1913 Suppl.]
OXFORD DICTIONARY
jackaroo, n. (also jackeroo) Austral. colloq. a novice on a sheep-station or cattle-station.
Etymology
JACK(1) + KANGAROO
For further exploring for "jackaroo" in Webster Dictionary Online