offsider

[ awf-sahy-der, of- ]
/ ˈɔfˈsaɪ dər, ˈɒf- /

noun Australian.

an assistant or helper.
a follower or supporter of a person or cause.

Origin of offsider

First recorded in 1875–80; offside + -er1

British Dictionary definitions for offsider

offsider
/ (ˌɒfˈsaɪdə) /

noun

Australian and NZ a partner or assistant