Ackman Share definition Flag Ackman is an Australian slang term for defecation. It was first used by Hugh Jackman. "Now, I need to go take what I like to call a "Huge Ackman". Ackman is Australian slang for shit. Don't look it up." Ackman by HJMs PR team October 17, 2023 0 0 Get merch Get the Ackman mug. Buy Now — $32.95 See more merch