| jab (n) | an injection by hypodermic needle |
| Jack Dancer | cancer rhyming slang |
| jackeroo (n) | cowboy |
| jacket potato (n) | baked potato with the skin on |
| jacking-up (v) | hassling someone |
| jaffle (n) | toasted sandwich |
| jam (n) | jelly |
| jamball donut (n) | jelly donut |
| jarrah (n) | a type of eucalyptus tree found in SW Western Australia, it produces a very hard, heavy wood used in furniture Also known as Swan River Mahogany, it was heavily logged and exported. At one point, the streets of London were paved with it. |
| jelly (n) | Jell-O |
| jillaroo (n) | cowgirl |
| jimjams (n) | pajamas (spelled pyjamas) |
| Joe Blake (n) | snake rhyming slang |
| joey (n) | baby kangaroo |
| joule (n) | metric measurement of energy equivalent to the calorie, short hand: J approx. 4.2 Joules per calorie |
| journo (n) | journalist |
| jug (n) | kettle, pitcher of beer |
| jumbuck (n) | sheep |
| jumped-up (adj) | one full of self-importance, arrogant |
| jumper (n) | sweatshirt, sweater, jersey "It's cold today, wear a jumper." |
| jumper punch (n) (v) | a technique in footy where one player grabs another's jumper (jersey) and punches him in the chest, making it look like they're grappling. Illegal, but hard to enforce. |
| just across the road (adj) | someplace nearby |