A brumby (also known as brumbyoz) is a new species of an Australian Dung Beetle that lives on the internet. It spreads filth on social media sites like Twitter and, unlike a real dung beetle, serves no useful purpose. It is also known to harass people (especially women) and exhibit an unwarranted savior complex but also shows cowardly behavior and runs away when confronted.
Look at that guy who is harassing women but doesn't have the guts to face up to them. He’s exhibiting pure brumby behavior.

A brumby has small balls but a big savior complex.
by Vir7us December 31, 2022
A synonym for wild horse in Australia. Brumbies are most commonly found in The Outback, Some parts of The Bush, The Blue Mountains and The Man From Snowy River.

Unlike cunt, macca's, copped and other Australian slang, Brumby is quite an old piece of jargon. As the word is mentioned in some of Banjo Patterson's early poems.
"Was driving from Perth to Alice Springs and out of no where... A bloody brumby jumped out from the bushes and in front of my car" - Aussie explaining how his car got wrecked

"There was movement at the station
For the world had passed around
that the Colt from Old Regret had got away
And he joined the wild bush Brumbies

He was worth a thousand pound
So all the cracks had gathered to the fray"
by Rossmoyne June 17, 2020
Bieng discreetly horny over a person
OMG he makes me so brumby
by Mayhonnaise April 22, 2019
A Brumby is commonly used as a way to call someone stupid without them realising. Mainly because of the fact that Brumbys seem a bit un-enlightened.
Did you hear about Ana, She is such a Brumby .
by Llat 051 February 16, 2017
a term developed in the early 2000's used to describe the commom jailbait nigger. commonly used by prison guards to decribe the targets of a newly developed sport called brumby-smashing. either that or to describe the anal rapage of a "brumby" in the showers.
Did you hear about toby? he got brumby-smashed yesterday!
by Brumbysmasher January 08, 2010